Remove "Start Element Call calls" permission

[hughns]

Your use case

What would you like to do?

The "Start Element Call calls" permission is no longer used and can be removed.

n.b. The "Join Element Call calls" is still relevant.

Why would you like to do it?

Remove the unnecessary UI.

How would you like to achieve it?

Have you considered any alternatives?

No response

Additional context

No response

[t3chguy]

The "Start Element Call calls" permission is no longer used and can be removed.

Can you explain why? https://github.com/matrix-org/matrix-spec-proposals/blob/matthew/group-voip/proposals/3401-group-voip.md#basic-call still seems to use m.call "Start Element Call calls"

[robintown]

That MSC is being superseded by MSC4143, which has no equivalent of m.call. In MatrixRTC, a call exists by virtue of there being some participants (m.rtc.member) joined to it.

[t3chguy]

@robintown okay then both options should be removed as they are MSC3401 only

[t3chguy]

Oh except https://github.com/matrix-org/matrix-spec-proposals/blob/toger5/matrixRTC/proposals/4143-matrix-rtc.md#unstable-prefix uses another MSC's unstable prefix. Is the SCT okay with this? Otherwise EW has an MSC3401 implementation seemingly by design