Support the widget API features needed for Element Call integration #7066
Description
Your use case
What would you like to do?
Implement MSC2762, MSC3819, and MSC3846 in Element Android
Why would you like to do it?
It's a prerequisite for integrating Element Call into Element Android, which is the future of VoIP in Element.
How would you like to achieve it?
Firstly, the most basic functionality of the widget API (negotiating capabilities, notifying the widget when the client is ready, etc.) needs to be implemented. Then, Element Android needs to add support for each of the MSCs listed above. Hopefully, both of these tasks can be greatly simplified by reusing the matrix-widget-api project, and referencing the matrix-react-sdk implementations linked on each of the MSCs.
Have you considered any alternatives?
No response
Additional context
No response
Are you willing to provide a PR?
No