CMake: List python source files as codegen dependencies (#83683)
The pyi, selected_mobile_ops and nvfuser code generators were missing
some dependencies outright. The autograd codegen had some effort to
list out specific files that it depends on, but this has clearly
fallen out of sync so it's safer to just depend on the entire folder.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/83683
Approved by: https://github.com/albanD
