Fix a few teleportation glitches

[Garanas]

Fixes a few teleportation glitches by checking if the unit can still teleport at the start and end of the teleportation sequence.

ACU starts with teleportation enhancement

ACU queues transport order, then teleportation order
Transport drops anywhere
ACU initiates the teleport but it able to do whatever it feels like

ACU starts with teleportation enhancement

ACU queues up a move order, queues up switching the enhancement, queues up a move order and then a teleport order
ACU moves, switches the enhancement, moves and then teleports even if it lost the enhancement

ACU starts with teleportation enhancement

ACU queues up the teleportation too close to the map border, ACU ends up outside the map being un targetable.