Nextcloud: Unauthorized force-mute from missing permission check when using internal signaling

Nextcloud is an open source content collaboration platform. Prior to versions 21.1.10, 22.0.11, and 23.0.3, a low-privileged user can force other user's microphones to be muted in calls when no High-performance Backend is installed. This issue has been patched in versions 21.1.10, 22.0.11, and 23.0.3.