[PyTorch] Fix unnecessary shared_ptr copies in DictType (#66702)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/66702
Missing moves in the construction path and forced copies of the key & value type on access.
ghstack-source-id: 140744707
Test Plan: CI
Reviewed By: suo
Differential Revision: D31693818
fbshipit-source-id: 4c5d2359f58148744621abe81429e56e7889f754
