Update playht tts service

src/examples/foundational/01-say-one-thing.py

@@ -4,6 +4,7 @@ import os
 
 from dailyai.services.daily_transport_service import DailyTransportService
 from dailyai.services.elevenlabs_ai_service import ElevenLabsTTSService
+from dailyai.services.playht_ai_service import PlayHTAIService
 
 from examples.foundational.support.runner import configure
 
@@ -26,10 +27,17 @@ async def main(room_url):
             meeting_duration_minutes,
             mic_enabled=True
         )
+        """
         tts = ElevenLabsTTSService(
             aiohttp_session=session,
             api_key=os.getenv("ELEVENLABS_API_KEY"),
             voice_id=os.getenv("ELEVENLABS_VOICE_ID"))
+        """
+        tts = PlayHTAIService(
+            api_key=os.getenv("PLAY_HT_API_KEY"),
+            user_id=os.getenv("PLAY_HT_USER_ID"),
+            voice_url=os.getenv("PLAY_HT_VOICE_URL"),
+        )
 
         # Register an event handler so we can play the audio when the participant joins.
         @transport.event_handler("on_participant_joined")