Revert "Update participants store from conversation data for guests"
Revert "Update participants store from conversation data for guests"

This was needed to know if a signaling message came from a moderator or
not in order to filter them. Now the filtering is done directly in the
server, so that code is no longer needed.

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

nextcloud/spreed,nextcloud/spreed,nextcloud/spreed