Fix joining calls with no media permission

You can still try to unmute your media in the preview screen and
the button will show unmuted, but then mute again once you actually
join, so not 100% perfect but better.

Fixes https://github.com/vector-im/element-call/issues/1907
Fixes https://github.com/vector-im/element-call/issues/1661

src/room/VideoPreview.tsx

@@ -82,6 +82,8 @@ export const VideoPreview: FC<Props> = ({
     },
     (error) => {
       logger.error("Error while creating preview Tracks:", error);
+      muteStates.audio.setEnabled?.(false);
+      muteStates.video.setEnabled?.(false);
     },
   );
   const videoTrack = useMemo(