Conference: first join, second can't maximize

Ok I digged a bit and here is the reason:

For the overlayMenu, we have "visible: isMe || meModerator" - But meModerator is incorrectly refreshed. When you join a conference and some members are already there, they will be displayed before we join the confInfo. So, meModerator will be false at this point (because we're not in the confInfo yet)

This is why it's caused for members that joined the conference before the moderator.

Some signaling must me re-done for ParticipantOverlay