Core/AreaTriggers: Handle exit areatrigger on player map change

Port From (https://github.com/TrinityCore/TrinityCore/commit/26fc14419142e3188370035ce4144cdb125bec05)

Source/Game/Entities/Unit/Unit.Fields.cs

@@ -101,6 +101,7 @@ namespace Game.Entities
         DiminishingReturn[] m_Diminishing = new DiminishingReturn[(int)DiminishingGroup.Max];
         protected List<GameObject> m_gameObj = new();
         List<AreaTrigger> m_areaTrigger = new();
+        List<AreaTrigger> m_insideAreaTriggers = new();
         protected List<DynamicObject> m_dynObj = new();
         protected float[] CreateStats = new float[(int)Stats.Max];
         float[] m_floatStatPosBuff = new float[(int)Stats.Max];

Source/Game/Entities/Unit/Unit.cs

@@ -877,6 +877,24 @@ namespace Game.Entities
             }
         }
 
+        public void EnterAreaTrigger(AreaTrigger areaTrigger)
+        {
+            m_insideAreaTriggers.Add(areaTrigger);
+        }
+
+        public void ExitAreaTrigger(AreaTrigger areaTrigger)
+        {
+            m_insideAreaTriggers.Remove(areaTrigger);
+        }
+
+        public void ExitAllAreaTriggers()
+        {
+            foreach (AreaTrigger at in m_insideAreaTriggers.ToList())
+                at.HandleUnitExit(this);
+        }
+
+        public List<AreaTrigger> GetInsideAreaTriggers() { return m_insideAreaTriggers; }
+
         public NPCFlags GetNpcFlags() { return (NPCFlags)m_unitData.NpcFlags.GetValue(); }
         public bool HasNpcFlag(NPCFlags flags) { return (m_unitData.NpcFlags & (uint)flags) != 0; }
         public void SetNpcFlag(NPCFlags flags) { SetUpdateFieldFlagValue(m_values.ModifyValue(m_unitData).ModifyValue(m_unitData.NpcFlags), (uint)flags); }