fix(Scripts/Arcatraz): Fix not being able to try Skyriss a second time after wipes (#17018)

* fix(Scripts/Arcatraz): Revive Warden Mellichar on wipes at Skyriss

* Update boss_harbinger_skyriss.cpp

src/server/scripts/Outland/TempestKeep/arcatraz/boss_harbinger_skyriss.cpp

@@ -73,6 +73,13 @@ struct boss_harbinger_skyriss : public BossAI
         });
     }
 
+    void EnterEvadeMode(EvadeReason why) override
+    {
+        BossAI::EnterEvadeMode(why);
+        instance->DoRespawnCreature(DATA_WARDEN_MELLICHAR, true);
+        me->DespawnOrUnsummon();
+    }
+
     void JustEngagedWith(Unit* /*who*/) override
     {
         Talk(SAY_AGGRO);