Fix stale fixture finalizers after setup errors

[MarthalaJagruthiReddy]

Summary

When a pytest_fixture_setup hook raises while setting up a parametrized fixture, FixtureDef.finish() returned early because cached_result was None. The post-finalizer remained queued, so the next parameter hit the assert not self._finalizers assertion and failed internally.

The same stale-finalizer state occurs with pytest's built-in async-fixture guard, where one unsupported async fixture can turn later tests into bare internal errors. Keep the early return only when there are no pending finalizers. This allows pending cleanup to run after setup failures and lets subsequent tests report their own results.

Fixes #14800

Tests

• PYTEST_DISABLE_PLUGIN_AUTOLOAD=1 uv run --frozen pytest -o minversion=0 testing/python/fixtures.py -q (241 passed, 3 xfailed)
• PYTEST_DISABLE_PLUGIN_AUTOLOAD=1 uv run --frozen pytest -o minversion=0 testing/acceptance_test.py -k 'sync_test_async_fixture or async_autouse_fixture' -q (4 passed)
• uvx ruff check src/_pytest/fixtures.py testing/python/fixtures.py testing/acceptance_test.py
• uvx ruff format --check src/_pytest/fixtures.py testing/python/fixtures.py testing/acceptance_test.py

Checklist

• Include new tests or update existing tests when applicable.
• Add text linking this PR to the issue.
• Create a changelog file in changelog/.
• Add yourself to AUTHORS.
• Allow maintainers to push and squash when merging my commits.
• If AI agents were used, they are credited in Co-authored-by commit trailers.