Update tests/client/transports/test_grpc_client.py

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

Author: cchinchilla-dev

tests/client/transports/test_grpc_client.py

@@ -558,6 +558,6 @@ def test_get_grpc_metadata_uses_lowercase_header_key(
     """Test gRPC metadata header key is always lowercase."""
     # Regression: gRPC rejects non-lowercase metadata keys
     metadata = grpc_transport._get_grpc_metadata(test_extensions)
-    assert metadata is not None
-    key, _ = metadata[0]
-    assert key == key.lower()
+    if metadata:
+        key, _ = metadata[0]
+        assert key == key.lower()