[pyupgrade] Fix UP007: ignore Optional[NamedTuple]

[robsdedude]

Summary

Make UP007 / UP045 ignore Optional[NamedTuple] as NamedTuple is a function (not a proper type). Rewriting it to NamedTuple | None breaks at runtime. While type checkers currently accept NamedTuple as a type, they arguably shouldn't. Therefore, we outright ignore it and don't touch or lint on it.

For a more detailed discussion, see the linked issue.

Test Plan

Added examples to the existing tests.

Related Issues

Fixes: #18619

[github-actions]

ruff-ecosystem results

Linter (stable)

✅ ecosystem check detected no linter changes.

Linter (preview)

✅ ecosystem check detected no linter changes.

[ntBre]

This is getting very slightly ahead of ourselves, but we're stabilizing UP045 and the preview behavior of UP007 in the upcoming release, which is taking place tomorrow. So could you update the tests in this file only to test the Union behavior? More generally, do we need to add tests for Union? I'm assuming an error is raised for NamedTuple | int, for example, not just NamedTuple | None.

[ntBre]

nit: I know it's not a good way to format real Python code, but I generally prefer adding new imports at the bottom of the file too, just to avoid shifting all of the existing snapshots and making the diff larger. Another option is moving the existing test file to a name like UP007_0.py and adding an entirely new fixture called UP007_1.py to accompany it.