[PyTorchEdge] Extend Flatbuffer to get mobile_info for NMLML workflows
Pull Request resolved: https://github.com/pytorch/pytorch/pull/78306
Extending the feature available from pickle that helps NMLML system get info of mobile models from `extra_files` dir
Differential Revision: [D36609548](https://our.internmc.facebook.com/intern/diff/D36609548/)
**NOTE FOR REVIEWERS**: This PR has internal Facebook specific changes or comments, please review them on [Phabricator](https://our.internmc.facebook.com/intern/diff/D36609548/)!
Approved by: https://github.com/iseeyuan