Core/Units: Added helper functions to modify UNIT_FLAG_UNINTERACTIBLE

Port From (https://github.com/TrinityCore/TrinityCore/commit/88ff97c1f96381565c47f8ca1993bdc7fce19fd6)

Source/Game/Entities/Unit/Unit.Combat.cs

@@ -147,7 +147,7 @@ namespace Game.Entities
             if (!IsAlive())
                 return false;
 
-            if (HasUnitFlag(UnitFlags.NonAttackable | UnitFlags.Uninteractible))
+            if (HasUnitFlag(UnitFlags.NonAttackable) || IsUninteractible())
                 return false;
 
             if (IsTypeId(TypeId.Player) && ToPlayer().IsGameMaster())

Source/Game/Entities/Unit/Unit.cs

@@ -3209,6 +3209,16 @@ namespace Game.Entities
 
         public virtual void SetImmuneToNPC(bool apply) { SetImmuneToNPC(apply, false); }
 
+        public bool IsUninteractible() { return HasUnitFlag(UnitFlags.Uninteractible); }
+
+        public void SetUninteractible(bool apply)
+        {
+            if (apply)
+                SetUnitFlag(UnitFlags.Uninteractible);
+            else
+                RemoveUnitFlag(UnitFlags.Uninteractible);
+        }
+
         public virtual float GetBlockPercent(uint attackerLevel) { return 30.0f; }
 
         void UpdateReactives(uint p_time)