[`Revert`] FSDP+Dtensor refactor related changes (#46246)
* Revert "init FSDP through from_pretrained (#46102)"
This reverts commit 0588858f54c8c79d28497d3ad6eac3417b716c49.
* Revert "Fix FSDP2 and distributed checkpointing imports for older PyTorch versions (#46141)"
This reverts commit 634500b9a9ce4a385b32acb71994156db52563d5.
* Revert "Update cohere2_moe tp_plan (#46189)"
This reverts commit e65c3a2d1461e6c43f6f5d4157c583846f63f71d.
* Revert "FSDP + TP & native save/load distributed (#45028)"
This reverts commit 9ba8e8585bbf6ed4c10455ef59c51c0da5f0b85f.
* fix
* they should have been deleted I think
* these are actually needed changes
* oops
