Add signedsource and generated header to build-types (#49259)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/49259

Also exclude `types_generated/` under ESLint + Prettier — paired with the removed `format` annotation.

Changelog: [Internal]

Reviewed By: j-piasecki

Differential Revision: D69306215

fbshipit-source-id: f2bfbeb3ce691ebf86b63fc498ae3847873c83ee