Telling only their client they joined spectators left the screen open, so the
admin had to unhide to get out. Move them to spectators and back to no team,
as css_hide does, with sv_disable_teamselect_menu on around it.
Hidden admins skip the team screen on reconnect (moved to spectators until re-hidden), never
receive the server's team menu message, and a pick from the screen M opens is answered by
telling only their client they joined spectators. The restore runs css_hide at most once, since
it toggles. Each command listener gets its own delegate: CSS keys listeners by handler, and
reusing one orphaned the first registration, which then swallowed its command.
