Make Element Call widget URL configurable server-side

[raphaelbadawi]

Your use case

What would you like to do?

For now we can configure element call (max participants, use_exclusively, and so on) client-side with config.json. But we can't do it with server discovery (.well_known).

Why would you like to do it?

This prevents us from having homogenous behavior between different client implementations (element legacy desktop, element web, element x, etc.) which is very problematic and can cause real life issues (example: 1 client would trigger legacy call while the other would have "use_exclusively" in config.json and trigger element call)

How would you like to achieve it?

Please just add it to the well_known (not just element.json) so it works with every client.

Have you considered any alternatives?

No response

Additional context

No response