[Quests] Use separate variable for quest idle override. (#4026)

* [Quests] Use separate variable for quest idle override.

* Fix missing zone->

zone/entity.cpp

@@ -525,7 +525,7 @@ void EntityList::MobProcess()
 			//	-- the entity's spawn2 point is marked as path_while_zone_idle
 			//	-- the zone is newly empty and we're allowing mobs to settle
 			if (
-				numclients > 0 ||
+				numclients > 0 || zone->quest_idle_override ||
 				(s2 && s2->PathWhenZoneIdle()) ||
 				mob_settle_timer->Enabled()
 			) {