fix(agents-api): Fix handling error message type

agents-api/agents_api/web.py

@@ -98,7 +98,10 @@ async def _handler(request: Request, exc: Exception):
                 offending_input = offending_input[loc]
 
                 # Keep only the message from the error
-                errors = [error.get("msg", error) for error in errors]
+                errors = [
+                    error.get("msg", error) if hasattr(error, "msg") else error
+                    for error in errors
+                ]
 
             else:
                 errors = exc.errors() if hasattr(exc, "errors") else [exc]