ruff

afe85e82 - [ty] Add mdtest for dataclass_transform field_descriptors compatibility (#23303)

[ty] Add mdtest for dataclass_transform field_descriptors compatibility (#23303) ## Summary This feature is currently only tested via an "externals" mdtest (the SQLModel one). I broke it in some other work and didn't find out until CI, since externals tests don't run by default. I think externals tests are very useful end-to-end validation, but ideally we should have specific feature coverage in non-externals mdtests, which are easier to understand and debug when they fail. ## Test Plan Test-only addition.