fix(token): use HasField to check token presence in TokenUnpauseTransaction._from_proto

Signed-off-by: anchit-goel <anchitgoel5@gmail.com>

Author: anchit-goel

src/hiero_sdk_python/tokens/token_unpause_transaction.py

@@ -82,7 +82,7 @@ def _from_proto(cls, proto: TokenUnpauseTransactionBody) -> TokenUnpauseTransact
         Returns:
             TokenUnpauseTransaction: A new instance of TokenUnpauseTransaction
         """
-        token_id = TokenId._from_proto(proto.token) if proto.token else None
+        token_id = TokenId._from_proto(proto.token) if proto.HasField("token") else None
         return cls(token_id=token_id)
 
     def _build_proto_body(self) -> TokenUnpauseTransactionBody:

tests/unit/token_unpause_transaction_test.py

@@ -170,6 +170,14 @@ def test_from_proto(mock_account_ids):
     assert unpause_tx.token_id.num == token_id.num
 
 
+def test_from_proto_without_token():
+    """Test creating a TokenUnpauseTransaction from protobuf representation without token."""
+    proto = TokenUnpauseTransactionBody()
+    unpause_tx = TokenUnpauseTransaction._from_proto(proto)
+
+    assert unpause_tx.token_id is None
+
+
 def test_upause_transaction_can_execute(mock_account_ids):
     """Test that a token upause transaction can be executed successfully."""
     _, _, _, token_id, _ = mock_account_ids