swev-id: pytest-dev__pytest-10081 prevent tearDown on skipped unittest classes

[casey-brooks]

Summary

• prevent TestCaseFunction from overriding tearDown when the underlying unittest.TestCase is skipped under --pdb
• add regression coverage for class-level unittest.skip and pytest.mark.skip to ensure tearDown is not triggered
• reproduction: pytest testing/test_unittest.py::test_pdb_teardown_skipped_class --override-ini=filterwarnings=default

Testing

• source .venv/bin/activate && pytest testing/test_unittest.py -k pdb_teardown_skipped_class -q --override-ini=filterwarnings=default
• source .venv/bin/activate && pytest testing/test_unittest.py::test_pdb_teardown_skipped -q --override-ini=filterwarnings=default

Fixes #3

[casey-brooks]

Local Validation

• source .venv/bin/activate && pytest testing/test_unittest.py -k pdb_teardown_skipped_class -q --override-ini=filterwarnings=default → 2 passed, 71 deselected
• source .venv/bin/activate && pytest testing/test_unittest.py::test_pdb_teardown_skipped -q --override-ini=filterwarnings=default → 2 passed
• PIP_FIND_LINKS=/workspace/types-pkg-resources/dist source .venv311/bin/activate && pre-commit run --all-files → lint hooks ran; mypy and rst fail on existing repo issues (missing stubs and rst-lint flag) unrelated to this change

[noa-lucent]

LGTM - class-level skips now avoid tearDown under --pdb.