Calling is possible even if power level is not sufficient

Describe the bug In a (modified) direct chat, a member who doesn’t have the power level to be able to send m.call.invite events, is still able to start a call. In encrypted rooms, the callee’s devices even start to ring. To Reproduce

1. Lower the power level for member A in a direct chat to n (< 100)
2. Set content['events']['m.call.invite'] = n + 1 in the state event m.room.power_levels.
3. Try to start a call from A’s device.
4. In encrypted rooms, B’s devices start ringing, in unencrypted rooms, I assume the event gets denied by the server, but still, Element Android shows the calling screen.

Expected behavior The buttons for audio and video calls should be disabled as soon as the power level is not anymore sufficient to start calls. Also, incoming calls from users not allowed to start them, should be swallowed.

Additional context

• App version 1.0.6 from Google Play
• Homeserver: Synapse 1.18

[enzingerm]

The main use case in my opinion is Matrix being used in kind of a “non symmetrical” relationship where for example a teacher wants to give his students the possibility to contact him but only in form of text messages, or a custodian offering his clients a “restricted” communication channel.

[TR-SLimey]

Just for clarity, the client on the receiving end should be responsible for dropping a call which is not allowed to be made by room permissions to prevent users from bypassing this room permission using a modified client. However, the sending client can still grey out the buttons for clarity and convenience.