ci: unpin `pyright`

[MarcoGorelli]

Pyright 1.1.409 is causing several type-checking errors:

./.venv/bin/uv run --no-sync pyright
/home/runner/work/narwhals/narwhals/narwhals/_dask/expr.py
  /home/runner/work/narwhals/narwhals/narwhals/_dask/expr.py:482:36 - error: Object of type "None" is not subscriptable (reportOptionalSubscript)
  /home/runner/work/narwhals/narwhals/narwhals/_dask/expr.py:497:35 - error: Object of type "None" is not subscriptable (reportOptionalSubscript)
/home/runner/work/narwhals/narwhals/narwhals/_dask/group_by.py
  /home/runner/work/narwhals/narwhals/narwhals/_dask/group_by.py:146:54 - error: "reset_index" is not a known attribute of "None" (reportOptionalMemberAccess)
/home/runner/work/narwhals/narwhals/narwhals/_ibis/namespace.py
  /home/runner/work/narwhals/narwhals/narwhals/_ibis/namespace.py:112:20 - error: Operator "/" not supported for types "Value" and "Value" (reportOperatorIssue)
  /home/runner/work/narwhals/narwhals/narwhals/_ibis/namespace.py:112:27 - error: Argument of type "Overload[(a: SupportsAdd[_T_contra@add, _T_co@add], b: _T_contra@add, /) -> _T_co@add, (a: _T_contra@add, b: SupportsRAdd[_T_contra@add, _T_co@add], /) -> _T_co@add]" cannot be assigned to parameter "function" of type "(_T@reduce, _T@reduce) -> _T@reduce" in function "reduce"
    No overloaded function matches type "(Value, Value) -> Value" (reportArgumentType)
  /home/runner/work/narwhals/narwhals/narwhals/_ibis/namespace.py:113:17 - error: Argument of type "Overload[(a: SupportsAdd[_T_contra@add, _T_co@add], b: _T_contra@add, /) -> _T_co@add, (a: _T_contra@add, b: SupportsRAdd[_T_contra@add, _T_co@add], /) -> _T_co@add]" cannot be assigned to parameter "function" of type "(_T@reduce, _T@reduce) -> _T@reduce" in function "reduce"
    No overloaded function matches type "(Value, Value) -> Value" (reportArgumentType)
/home/runner/work/narwhals/narwhals/narwhals/_polars/dataframe.py
  /home/runner/work/narwhals/narwhals/narwhals/_polars/dataframe.py:485:29 - error: No overloads for "__getitem__" match the provided arguments (reportCallIssue)
  /home/runner/work/narwhals/narwhals/narwhals/_polars/dataframe.py:485:29 - error: Argument of type "slice[int | Any | str | None, Any | int | str | None, Any | int]" cannot be assigned to parameter "s" of type "slice[SupportsIndex | None, SupportsIndex | None, SupportsIndex | None]" in function "__getitem__"
    "slice[int | Any | str | None, Any | int | str | None, Any | int]" is not assignable to "slice[SupportsIndex | None, SupportsIndex | None, SupportsIndex | None]"
      Type parameter "_StartT_co@slice" is covariant, but "int | Any | str | None" is not a subtype of "SupportsIndex | None"
        Type "int | Any | str | None" is not assignable to type "SupportsIndex | None"
          Type "str" is not assignable to type "SupportsIndex | None"
            "str" is incompatible with protocol "SupportsIndex"
            "str" is not assignable to "None"
      Type parameter "_StopT_co@slice" is covariant, but "Any | int | str | None" is not a subtype of "SupportsIndex | None"
        Type "Any | int | str | None" is not assignable to type "SupportsIndex | None" (reportArgumentType)
/home/runner/work/narwhals/narwhals/narwhals/_sql/expr.py
  /home/runner/work/narwhals/narwhals/narwhals/_sql/expr.py:468:17 - error: Argument of type "NativeExprT@SQLExpr" cannot be assigned to parameter "b" of type "SupportsRMul[_T_contra@mul, _T_co@mul]" in function "mul"
    "NativeExpr*" is incompatible with protocol "SupportsRMul[NativeExprT@SQLExpr, _T_co@mul]"
      "__rmul__" is not present (reportArgumentType)
  /home/runner/work/narwhals/narwhals/narwhals/_sql/expr.py:468:40 - error: No overloads for "sub" match the provided arguments (reportCallIssue)
  /home/runner/work/narwhals/narwhals/narwhals/_sql/expr.py:468:59 - error: Argument of type "Literal[1]" cannot be assigned to parameter "b" of type "SupportsRSub[_T_contra(1)@sub, _T_co(1)@sub]" in function "sub"
    "Literal[1]" is incompatible with protocol "SupportsRSub[NativeExprT@SQLExpr, _T_co(1)@sub]"
      Type parameter "_T_contra@SupportsRSub" is contravariant, but "int" is not a supertype of "NativeExprT@SQLExpr"
        "NativeExpr*" is not assignable to "int" (reportArgumentType)
  /home/runner/work/narwhals/narwhals/narwhals/_sql/expr.py:468:65 - error: No overloads for "sub" match the provided arguments (reportCallIssue)
  /home/runner/work/narwhals/narwhals/narwhals/_sql/expr.py:468:83 - error: Argument of type "int" cannot be assigned to parameter "b" of type "SupportsRSub[_T_contra(2)@sub, _T_co(2)@sub]" in function "sub"
    "int" is incompatible with protocol "SupportsRSub[NativeExprT@SQLExpr, _T_co(2)@sub]"
      Type parameter "_T_contra@SupportsRSub" is contravariant, but "int" is not a supertype of "NativeExprT@SQLExpr"
        "NativeExpr*" is not assignable to "int" (reportArgumentType)
  /home/runner/work/narwhals/narwhals/narwhals/_sql/expr.py:482:17 - error: No overloads for "sub" match the provided arguments (reportCallIssue)
  /home/runner/work/narwhals/narwhals/narwhals/_sql/expr.py:482:35 - error: Argument of type "Literal[1]" cannot be assigned to parameter "b" of type "SupportsRSub[_T_contra@sub, _T_co@sub]" in function "sub"
    "Literal[1]" is incompatible with protocol "SupportsRSub[NativeExprT@SQLExpr, _T_co@sub]"
      Type parameter "_T_contra@SupportsRSub" is contravariant, but "int" is not a supertype of "NativeExprT@SQLExpr"
        "NativeExpr*" is not assignable to "int" (reportArgumentType)
  /home/runner/work/narwhals/narwhals/narwhals/_sql/expr.py:482:40 - error: No overloads for "sub" match the provided arguments (reportCallIssue)
  /home/runner/work/narwhals/narwhals/narwhals/_sql/expr.py:482:58 - error: Argument of type "int" cannot be assigned to parameter "b" of type "SupportsRSub[_T_contra(1)@sub, _T_co(1)@sub]" in function "sub"
    "int" is incompatible with protocol "SupportsRSub[NativeExprT@SQLExpr, _T_co(1)@sub]"
      Type parameter "_T_contra@SupportsRSub" is contravariant, but "int" is not a supertype of "NativeExprT@SQLExpr"
        "NativeExpr*" is not assignable to "int" (reportArgumentType)
  /home/runner/work/narwhals/narwhals/narwhals/_sql/expr.py:530:17 - error: Argument of type "NativeExprT@SQLExpr" cannot be assigned to parameter "b" of type "SupportsRAdd[_T_contra@add, _T_co@add]" in function "add"
    "NativeExpr*" is incompatible with protocol "SupportsRAdd[NativeExprT@SQLExpr, _T_co@add]"
      "__radd__" is not present (reportArgumentType)
  /home/runner/work/narwhals/narwhals/narwhals/_sql/expr.py:537:17 - error: No overloads for "add" match the provided arguments (reportCallIssue)
  /home/runner/work/narwhals/narwhals/narwhals/_sql/expr.py:539:21 - error: Argument of type "NativeExprT@SQLExpr" cannot be assigned to parameter "b" of type "SupportsRAdd[_T_contra@add, _T_co@add]" in function "add"
    "NativeExpr*" is incompatible with protocol "SupportsRAdd[NativeExprT@SQLExpr, _T_co@add]"
      "__radd__" is not present (reportArgumentType)
  /home/runner/work/narwhals/narwhals/narwhals/_sql/expr.py:698:17 - error: No overloads for "sub" match the provided arguments (reportCallIssue)
  /home/runner/work/narwhals/narwhals/narwhals/_sql/expr.py:698:30 - error: Argument of type "NativeExprT@SQLExpr" cannot be assigned to parameter "b" of type "SupportsRSub[_T_contra@sub, _T_co@sub]" in function "sub"
    "NativeExpr*" is incompatible with protocol "SupportsRSub[NativeExprT@SQLExpr, _T_co@sub]"
      "__rsub__" is not present (reportArgumentType)
  /home/runner/work/narwhals/narwhals/narwhals/_sql/expr.py:834:21 - error: No overloads for "add" match the provided arguments (reportCallIssue)
  /home/runner/work/narwhals/narwhals/narwhals/_sql/expr.py:836:25 - error: Argument of type "NativeExprT@SQLExpr" cannot be assigned to parameter "b" of type "SupportsRAdd[_T_contra@add, _T_co@add]" in function "add"
    "NativeExpr*" is incompatible with protocol "SupportsRAdd[NativeExprT@SQLExpr, _T_co@add]"
      "__radd__" is not present (reportArgumentType)
  /home/runner/work/narwhals/narwhals/narwhals/_sql/expr.py:844:25 - error: No overloads for "sub" match the provided arguments (reportCallIssue)
  /home/runner/work/narwhals/narwhals/narwhals/_sql/expr.py:844:75 - error: Argument of type "NativeExprT@SQLExpr" cannot be assigned to parameter "b" of type "SupportsRSub[_T_contra@sub, _T_co@sub]" in function "sub"
    "NativeExpr*" is incompatible with protocol "SupportsRSub[NativeExprT@SQLExpr, _T_co@sub]"
      "__rsub__" is not present (reportArgumentType)
/home/runner/work/narwhals/narwhals/narwhals/_sql/expr_str.py
  /home/runner/work/narwhals/narwhals/narwhals/_sql/expr_str.py:70:17 - error: No overloads for "add" match the provided arguments (reportCallIssue)
  /home/runner/work/narwhals/narwhals/narwhals/_sql/expr_str.py:70:42 - error: Argument of type "NativeExpr" cannot be assigned to parameter "b" of type "SupportsRAdd[_T_contra@add, _T_co@add]" in function "add"
    "NativeExpr" is incompatible with protocol "SupportsRAdd[NativeExpr, _T_co@add]"
      "__radd__" is not present (reportArgumentType)
/home/runner/work/narwhals/narwhals/narwhals/_sql/namespace.py
  /home/runner/work/narwhals/narwhals/narwhals/_sql/namespace.py:63:17 - error: Argument of type "Overload[(a: SupportsAdd[_T_contra@add, _T_co@add], b: _T_contra@add, /) -> _T_co@add, (a: _T_contra@add, b: SupportsRAdd[_T_contra@add, _T_co@add], /) -> _T_co@add]" cannot be assigned to parameter "function" of type "(_T@reduce, _T@reduce) -> _T@reduce" in function "reduce"
    No overloaded function matches type "(NativeExprT@SQLNamespace, NativeExprT@SQLNamespace) -> NativeExprT@SQLNamespace" (reportArgumentType)
29 errors, 0 warnings, 0 informations
make: *** [Makefile:26: typing] Error 1

I'm temporarily pinning pyright to get CI green, but we should fix these