fix: readonly type changes

[ethanalvizo]

Updated types to pass CI check for this PR: https://github.com/deephaven-ent/iris/pull/3775

JIRA ticket created to update JS API types: https://deephaven.atlassian.net/browse/DH-21450

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 45.93%. Comparing base (0872767) to head (dd1f38e).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2610      +/-   ##
==========================================
- Coverage   45.94%   45.93%   -0.01%     
==========================================
  Files         771      771              
  Lines       43680    43680              
  Branches    11239    11239              
==========================================
- Hits        20069    20065       -4     
- Misses      23566    23598      +32     
+ Partials       45       17      -28     

Flag	Coverage Δ
unit	45.93% <100.00%> (-0.01%)	⬇️

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