Core/AI Prevent bosses respawn when BossState is set to DONE (#17616)

src/server/game/AI/ScriptedAI/ScriptedCreature.cpp

@@ -507,6 +507,14 @@ void BossAI::_EnterCombat()
     ScheduleTasks();
 }
 
+bool BossAI::CanRespawn()
+{
+    if (instance && instance->GetBossState(_bossId) == DONE)
+        return false;
+
+    return true;
+}
+
 void BossAI::TeleportCheaters()
 {
     float x, y, z;

src/server/game/AI/ScriptedAI/ScriptedCreature.h

@@ -361,6 +361,7 @@ class BossAI : public ScriptedAI
         void JustReachedHome() override { _JustReachedHome(); }
 
         bool CanAIAttack(Unit const* target) const override { return CheckBoundary(target); }
+        bool CanRespawn() override;
 
     protected:
         void _Reset();