Core/SmartAI: SmartAI creatures no longer process health-based hooks after death.

Port From (https://github.com/TrinityCore/TrinityCore/commit/3db58c4d96c446b736b84d4954f8fd9c9e309e33)

Source/Game/AI/SmartScripts/SmartAI.cs

@@ -322,6 +322,13 @@ namespace Game.AI
 
         public override void UpdateAI(uint diff)
         {
+            if (!me.IsAlive())
+            {
+                if (IsEngaged())
+                    EngagementOver();
+                return;
+            }
+
             CheckConditions(diff);
 
             GetScript().OnUpdate(diff);

Source/Game/Entities/Creature/Creature.cs

@@ -2176,7 +2176,7 @@ namespace Game.Entities
 
         public void CallForHelp(float radius)
         {
-            if (radius <= 0.0f || !IsEngaged() || IsPet() || IsCharmed())
+            if (radius <= 0.0f || !IsEngaged() || !IsAlive() || IsPet() || IsCharmed())
                 return;
 
             Unit target = GetThreatManager().GetCurrentVictim();
@@ -2187,7 +2187,7 @@ namespace Game.Entities
 
             if (target == null)
             {
-                Log.outError(LogFilter.Unit, $"Creature {GetEntry()} ({GetName()}) is engaged without threat list");
+                Log.outError(LogFilter.Unit, $"Creature {GetEntry()} ({GetName()}) trying to call for help without being in combat.");
                 return;
             }