[Auto Sync] Update protocol.py (20250923) (#10820)

Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
Co-authored-by: cicirori <32845984+cicirori@users.noreply.github.com>

python/sglang/srt/entrypoints/openai/protocol.py

@@ -339,7 +339,7 @@ class FunctionResponse(BaseModel):
     """Function response."""
 
     name: Optional[str] = None
-    arguments: Optional[str] = None
+    arguments: Optional[str | Dict[str, Any]] = None
 
 
 class ToolCall(BaseModel):