Stop sent streams for initially disabled media
Stop sent streams for initially disabled media

Besides reacting to disable state changes the sent streams are also
stopped now when tracks are initially disabled and no event is emitted.

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

nextcloud/spreed,nextcloud/spreed,nextcloud/spreed