Fixed: when teleporting between grids, the avatar name wasn't always updated.

When an avatar is in their home grid, their name appears as "First Last". In other grids the name appears as "First.Last @grid.example.com". However, viewers have a bug and they don't always show the new name. We use a trick (changing the Group Title briefly) in order to make the viewers show the new name. This is only done after a Hypergrid teleport.