[DCP][BE] Remove unused fields (#116245)

As title

Differential Revision: [D52357730](https://our.internmc.facebook.com/intern/diff/D52357730/)

Pull Request resolved: https://github.com/pytorch/pytorch/pull/116245
Approved by: https://github.com/wz337
diff --git a/torch/distributed/checkpoint/metadata.py b/torch/distributed/checkpoint/metadata.py
index 4ce6250..bd13ee9 100644
--- a/torch/distributed/checkpoint/metadata.py
+++ b/torch/distributed/checkpoint/metadata.py
@@ -2,7 +2,6 @@
 from typing import Any, Dict, List, Optional, Sequence, Union
 
 import torch
-from torch.distributed._shard.sharded_tensor import ShardedTensor
 from torch.distributed._shard.sharded_tensor.metadata import TensorProperties
 from torch.distributed.checkpoint.stateful import StatefulT
 
@@ -35,7 +34,6 @@
     pass
 
 
-TENSOR_TYPE = Union[torch.Tensor, ShardedTensor]
 STORAGE_TYPES = Union[TensorStorageMetadata, BytesStorageMetadata]
 STATE_DICT_TYPE = Dict[str, Union[StatefulT, Any]]