feat(silent): hide unmute if participant joined without audio

[nbeckindy]

A fix for this issue I submitted earlier: #14559

Not sure if this is the way you'd want to go about resolving this problem, but this is how we handled it.

Depends on this PR in the lib-jitsi-meet repo: jitsi/lib-jitsi-meet#2534

[jitsi-jenkins]

Hi, thanks for your contribution!
If you haven't already done so, could you please make sure you sign our CLA (https://jitsi.org/icla for individuals and https://jitsi.org/ccla for corporations)? We would unfortunately be unable to merge your patch unless we have that piece :(.

[damencho]

Why do we need it and here, isn't the one in base/conference/actions.any.ts enough?

[nbeckindy]

I thought the same thing, but if I remove the listener from conference.js, other browser-based participants don't see the silent status. And if I remove the listener in base/conference/actions.any.ts, mobile app participants don't see the status. I could only get it to work on both platforms with both of these listeners. I never could figure out why that's the case though.