Avatar shadow mode 2 is broken

[Chorazin Allen]

See https://sourceforge.net/p/team-purple/kokua/tickets/508/ for the detail.

Basically, mode 2 only casts a mesh shadow once and that shadow does not move with the avatar.

Although reported on Kokua, I've tested with same results on 2.9.23.0 and 2.9.23.1

[Marine Kelley]

Fixed in RLV 2.9.24 (updated the code from Firestorm which already had the fix)