Update examples to align with latest best practices

examples/foundational/07c-interruptible-deepgram-vad.py

@@ -16,7 +16,7 @@ from runner import configure
 
 from pipecat.frames.frames import (
     BotInterruptionFrame,
-    LLMMessagesFrame,
+    EndFrame,
     StopInterruptionFrame,
     UserStartedSpeakingFrame,
     UserStoppedSpeakingFrame,
@@ -80,7 +80,15 @@ async def main():
             ]
         )
 
-        task = PipelineTask(pipeline, PipelineParams(allow_interruptions=True))
+        task = PipelineTask(
+            pipeline,
+            PipelineParams(
+                allow_interruptions=True,
+                enable_metrics=True,
+                enable_usage_metrics=True,
+                report_only_initial_ttfb=True,
+            ),
+        )
 
         @stt.event_handler("on_speech_started")
         async def on_speech_started(stt, *args, **kwargs):
@@ -94,7 +102,11 @@ async def main():
         async def on_first_participant_joined(transport, participant):
             # Kick off the conversation.
             messages.append({"role": "system", "content": "Please introduce yourself to the user."})
-            await task.queue_frames([LLMMessagesFrame(messages)])
+            await task.queue_frames([context_aggregator.user().get_context_frame()])
+
+        @transport.event_handler("on_participant_left")
+        async def on_participant_left(transport, participant, reason):
+            await task.queue_frame(EndFrame())
 
         runner = PipelineRunner()