Fix ruff lint and bitwise XOR on float32 in indicator test

Remove blank line between import groups (ruff check) and cast
float32 slices to int32 before applying bitwise XOR to fix
TypeError on numpy versions that enforce safe casting.

Author: PavelGuzenfeld

tests/python/test_parse_tree.py

@@ -1,6 +1,5 @@
 import numpy as np
 import pytest
-
 import xgboost as xgb
 from xgboost import testing as tm
 from xgboost.testing.parse_tree import (
@@ -60,7 +59,9 @@ def test_tree_to_df_indicator(self, tmp_path) -> None:
         n_samples = 200
         n_features = 5
         X = rng.randint(0, 2, size=(n_samples, n_features)).astype(np.float32)
-        y = (X[:, 0] ^ X[:, 1]).astype(np.float32)
+        y = (X[:, 0].astype(np.int32) ^ X[:, 1].astype(np.int32)).astype(
+            np.float32
+        )
         dtrain = xgb.DMatrix(X, label=y)
 
         # Create a feature map with indicator type 'i'