Fix lateness update transaction

Author: jjoonleo

ontime-back/src/main/java/devkor/ontime_back/service/ScheduleService.java

@@ -172,6 +172,7 @@ public List<LatenessHistoryResponse> getLatenessHistory(Long userId) {
     }
 
     // 지각 시간 업데이트
+    @Transactional
     public void updateLatenessTime(Schedule schedule, Integer latenessTime) {
         schedule.updateLatenessTime(latenessTime);
         scheduleRepository.save(schedule);