feat(screenshare): support remote wireless screensharing (#3809)
* feat(screenshare): support remote wireless screensharing
- Pass events to the ProxyConnectionService so it can
handle establishing a peer connection so a remote
participant, not in the conference, can send a
video stream to the local participant to use as a
local desktop stream.
- Modify the existing start screensharing flow to accept
a desktop stream instead of always trying to create one.
* adjust ProxyConnectionService for lib review changes