fix(vertex_httpx.py): support passing response_schema to gemini

litellm/utils.py

@@ -2756,6 +2756,11 @@ def get_optional_params(
             non_default_params=non_default_params,
             optional_params=optional_params,
             model=model,
+            drop_params=(
+                drop_params
+                if drop_params is not None and isinstance(drop_params, bool)
+                else False
+            ),
         )
     elif (
         custom_llm_provider == "vertex_ai" and model in litellm.vertex_anthropic_models