examples: update to use on_function_calls_started event

examples/foundational/14-function-calling.py

@@ -30,7 +30,6 @@ load_dotenv(override=True)
 
 
 async def fetch_weather_from_api(params: FunctionCallParams):
-    await params.llm.push_frame(TTSSpeakFrame("Let me check on that."))
     await params.result_callback({"conditions": "nice", "temperature": "75"})
 
 
@@ -72,6 +71,10 @@ async def run_example(transport: BaseTransport, _: argparse.Namespace, handle_si
     # sent to the same callback with an additional function_name parameter.
     llm.register_function("get_current_weather", fetch_weather_from_api)
 
+    @llm.event_handler("on_function_calls_started")
+    async def on_function_calls_started(service, function_calls):
+        await tts.queue_frame(TTSSpeakFrame("Let me check on that."))
+
     weather_function = FunctionSchema(
         name="get_current_weather",
         description="Get the current weather",