Core/Units: moved health and power ordering predicates from Unit header into CommonPredicates

Port From (https://github.com/TrinityCore/TrinityCore/commit/2f6ed2c203b16a1d1e85f61a8b8e2cf3d1a4e784)

Source/Game/Spells/Spell.cs

@@ -11,6 +11,7 @@ using Game.DataStorage;
 using Game.Entities;
 using Game.Loots;
 using Game.Maps;
+using Game.Miscellaneous;
 using Game.Movement;
 using Game.Networking.Packets;
 using Game.Scripting;