Dispatch "cloned" event when cloning a MediaStreamTrack
Dispatch "cloned" event when cloning a MediaStreamTrack

Cloning a track was a "silent" operation, so it was not possible to keep
track of all the created MediaStreamTracks. Dispatching an event when a
track is cloned will make possible to do that.

Signed-off-by: Daniel Calviño Sánchez <bd7629e975cc0e00ea7cda4ab6a120f2ee42ac1b@gmail.com>

nextcloud/spreed,nextcloud/spreed,nextcloud/spreed