Units with non-human pawns cannot use voicepacks #1508

In XGUnit.UnitSpeak, the code checks if the unit is an alien based on character type. This prevents some mod-added units such as playable aliens, Allies Unknown, etc from being able to allow voicepacks since many of these units are marked as Alien on the character template to avoid issues such as Spectre Shadowbind attempting to target a non-human enemy.

This check simply checks the unit's character template via UnitState.IsAlien

Solution: add some way to override this check. A basic example I tested was updating the return statement to return UnitState.IsAlien() && !UnitState.IsSoldier(); so that units that are marked as soldiers can speak but not allow other units to speak. This fixed the specific case I tested but may not be as comprehensive.