[FSDP][optim_state_dict] Make FSDP.optim_state_dict compatbile with DMP (#93285)
`torchrec.DistributedModelParallel` overwrites `named_parameters` and is not compatible with `FullyShardedDataParallel`'s optim_state_dict. This PR adds some workaround in `FullyShardedDataParallel` to make both work together.
Differential Revision: [D42764611](https://our.internmc.facebook.com/intern/diff/D42764611/)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/93285
Approved by: https://github.com/rohan-varma
