fix: use getattr on error if it's not a dictionary

agents-api/agents_api/web.py

@@ -100,7 +100,7 @@ async def _handler(request: Request, exc: Exception):
 
                 # Keep only the message from the error
                 errors = [
-                    error.get("msg", error) if hasattr(error, "msg") else error
+                    error.get("msg", error) if isinstance(error, dict) else getattr(error, "msg", error)
                     for error in errors
                 ]