Add annotations to torchrec/sparse/jagged_tensor.py (#1645)

Summary: Pull Request resolved: #1645

Reviewed By: azad-meta

Differential Revision: D52957242

fbshipit-source-id: 44b4c12a490b8ed66e9e1d36c9b9c7eaf851f840

torchrec/sparse/jagged_tensor.py

@@ -33,7 +33,7 @@
     from torch._dynamo import is_compiling as is_torchdynamo_compiling
 except Exception:
 
-    def is_torchdynamo_compiling():  # type: ignore[misc]
+    def is_torchdynamo_compiling() -> bool:  # type: ignore[misc]
         return False