fix: #2760 wait for realtime response.done before follow-up response.create (#2763)

Author: seratch

examples/realtime/app/agent.py

@@ -90,6 +90,7 @@ def get_weather(city: str) -> str:
         f"{RECOMMENDED_PROMPT_PREFIX} "
         "You are a helpful triaging agent. You can use your tools to delegate questions to other appropriate agents."
     ),
+    tools=[get_weather],
     handoffs=[faq_agent, realtime_handoff(seat_booking_agent)],
 )