TTS Steaming is Broken for livekit-plugins-elevenlabs v0.4.0

[technoligest]

This is a more clear description + RCA of #279

I think the issue is related to the TTS streaming implementation of livekit-plugins-elevenlabs. The reason I think that is because when I comment out this code from the assistant.py code, the very first assistant.say call is sent down to the agent playground.

Debugging further, I was able to verify that OpenAI is sending down the correct response to voices, but it wasn't getting streamed as audio to the playground.

I also tried downgrading to all the 0.4.0 dev versions, and none of them fixed the issue. 0.3.0 didn't work at all with the other packages.

The product code I'm using is the official agents quickstart guide.