Support start chatting on wake

[uezo]

• Wakeword -> Prompt -> User request -> AI response
• Wakeword -> (Use wakeword as request) -> AI response <= Support this flow

To use wakeword as the request, make on_wakeword like below:

async def on_wakeword(text):
    logger.info(f"Wakeword: {text}")
    await app.start_chat(request_on_start=text, skip_start_voice=True)