feat: 트랜잭션 전파 옵션 변경

server/src/main/java/haengdong/event/application/EventService.java

@@ -243,7 +243,7 @@ private void deleteEvent(String token, Long userId) {
     }
 
     @Async
-    @Transactional
+    @Transactional(propagation = Propagation.REQUIRES_NEW)
     @TransactionalEventListener(phase = TransactionPhase.AFTER_COMMIT)
     public void handleUserDelete(UserDeleteEvent userDeleteEvent) {
         Long userId = userDeleteEvent.id();