[torch.Package] Folder has_file() method (#56584)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/56584
Test Plan: Imported from OSS
Reviewed By: suo
Differential Revision: D27909314
Pulled By: Lilyjjo
fbshipit-source-id: facc89735ab67c87f0ec7653d8ccc359f98d4e0d
