[PyTorch Edge] Skip writing version during backport (#65842)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/65842
During backport, only parts of the model (like bytecode.pkl) needs to be re-written, while the rest of the model is the same. However, `version` will always be re-written when `PyTorchStreamWriter` is destrcuted.
Change version to optional and add an api to allow skipping writing version when closing the writer.
ghstack-source-id: 139580386
Test Plan: buck run papaya/scripts/repro:save_load
Reviewed By: iseeyuan, tugsbayasgalan
Differential Revision: D31262904
fbshipit-source-id: 3b8a5e1aaa610ffb0fe8a616d9ad9d0987c03f23
