Voice: allow to respond chat contents with voice for a true conversation #196261
Description
Now I want to hear Copilot respond. It is a nice pair, I talk and I hear the response back. Ideally there is some easy toggle to mute Copilot.
### Tasks
- [x] Explore UI of others (Bing, OpenAI)
- [x] Auto synthesise when voice was used by changing mic icon to speaker icon
- [x] Have action per chat block to synthesize
- [x] Explore SML: can it be used to control playback speed or skip over code?