[fx] add missing modules for type annoations (#47537)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/47537
When a module only appears in a type constructor List[torch.Tensor],
it previously didn't get added to the list of used modules. This fixes it
by introspecting on the type constructor.
Test Plan: Imported from OSS
Reviewed By: jamesr66a
Differential Revision: D24806317
Pulled By: zdevito
fbshipit-source-id: 263391af71e1f2156cbefaab95b9818c6b9aaae1
