[_shard] only check shard metadata for copy_ (#82655)
copy_ does not restrict on tensor properites, it does not check things like requires_grad or dtype, so only check if the shard metadata are the same
Differential Revision: [D38359176](https://our.internmc.facebook.com/intern/diff/D38359176/)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/82655
Approved by: https://github.com/fduwjj
