fix(Scripts/BossAI): add optional variable to BossAI class to make sure the boss calls for help (#18630)

init

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

@@ -462,6 +462,8 @@ public:
     BossAI(Creature* creature, uint32 bossId);
     ~BossAI() override {}
 
+    float callForHelpRange;
+
     InstanceScript* const instance;
 
     bool CanRespawn() override;