Add multiple media handler plugin support in calls

Currently calls only support having one plugin enabled at a time. The case where multiple are enabled will cause all sorts of undefined behaviour.

marked this issue as related to #1493

marked this issue as blocked by #1492

To meaningfully be able to test this will require having at least two functional call media plugins on the client, which currently isn't the case.

Whisper/GreenScreen/Watermark are 3 different plugins.

I was under the impression that only watermark worked at all but I'll check again.

Can you also enable plugins (one or more) during a call?

yes

And also install plugins during a call and enable them like Whisper and/or GreenScreen?

You should already be able to enable plugins during a call. There are just some problems when enabling several at once that need to be checked for and fixed.

OK - Thx for info!

added plugins typerefactor labels