Force MusicianComm channel in last position

[LenweSaralonde]

Sometimes regular General / Trade / LocalDefense take too much time to be joint and MusicianComm gets in first position.

Solution: Reorder channels every time the channel list is changed to force MusicianComm at the last position

[LenweSaralonde]

The CHAT_MSG_CHANNEL_NOTICE event is not always triggered when joining the standard General, Trade and Local Defense channels so in rare occasions, the channels are not reordered at login.

The channels are now also reordered on CHANNEL_UI_UPDATE which is properly triggered every time a new channel is joined.

Fixed in a9e4d2e (retail) and 8655a0b (classic)