ADK changes

PiperOrigin-RevId: 810223422

Author: xuanyang15

src/google/adk/tools/openapi_tool/openapi_spec_parser/operation_parser.py

@@ -164,8 +164,8 @@ def _dedupe_param_names(self):
   def _process_return_value(self) -> Parameter:
     """Returns a Parameter object representing the return type."""
     responses = self._operation.responses or {}
-    # Default to Any if no 2xx response or if schema is missing
-    return_schema = Schema(type='Any')
+    # Default to empty schema if no 2xx response or if schema is missing
+    return_schema = Schema()
 
     # Take the 20x response with the smallest response code.
     valid_codes = list(