fix(Scripts/Gundrak): Fix Drakkari Colossus not activating when Living Mojo is attacked (#25214)

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

src/server/scripts/Northrend/Gundrak/boss_drakkari_colossus.cpp

@@ -363,7 +363,7 @@ public:
             ScriptedAI::MoveInLineOfSight(who);
         }
 
-        void AttackStart(Unit* who) override
+        void JustEngagedWith(Unit* who) override
         {
             if (me->ToTempSummon())
             {
@@ -373,6 +373,14 @@ public:
                 return;
             }
 
+            ScriptedAI::JustEngagedWith(who);
+        }
+
+        void AttackStart(Unit* who) override
+        {
+            if (me->ToTempSummon())
+                return;
+
             ScriptedAI::AttackStart(who);
         }