Fix raised hand handler not detached when peer is destroyed
Fix raised hand handler not detached when peer is destroyed

This fixes a memory leak, as the reference to the Peer object was
retained forever by the webrtc object.

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

nextcloud/spreed,nextcloud/spreed,nextcloud/spreed