[pytree] Properly register immutable collections (#120036)
Summary:
Getting error like:
```
No registered serialization name for <class 'torch.fx.immutable_collections.immutable_dict'> found. Please update your _register_pytree_node call with a `serialized_type_name` kwarg.
```
Reviewed By: suo
Differential Revision: D53833323
Pull Request resolved: https://github.com/pytorch/pytorch/pull/120036
Approved by: https://github.com/SherlockNoMad
