Update prompts.yaml

prompts.yaml

@@ -320,6 +320,7 @@
     Here is the final answer from your managed agent '{{name}}':
     {{final_answer}}
 
-"final_answer": |
-  Here is the final answer:
-  {answer}
+"final_answer":
+  "pre_messages": |
+    Here is the final answer:
+    {answer}