chore: fix pytest crash on pandas 3.0 due to missing SettingWithCopyWarning

[google-labs-jules]

Moved ignore::pandas.errors.SettingWithCopyWarning from pytest.ini to conftest.py with a check for its existence. This fixes AttributeError: module 'pandas.errors' has no attribute 'SettingWithCopyWarning' when running tests against pandas 3.0.

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PR created automatically by Jules for task 1336882389279070030 started by @tswast

[google-labs-jules]

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