TST: Replace ensure_clean_store with tmp_path in io/pytables/test_categorical.py

[HuilinXu]

What does this PR do?

• Update pandas/tests/io/pytables/test_categorical.py from using the custom ensure_clean_store utility to the standard pytest tmp_path fixture.

Why is this change needed?

• Issue TST: Replace ensure_clean utility function with the temp_file pytest fixture #62435

Testing

• All existing tests pass
• No behavioral changes to the tests

[mroeschke]

Thanks @HuilinXu