refactor: 2차 정렬 기준 추가

backend/src/main/java/reviewme/review/repository/AnswerRepository.java

@@ -15,7 +15,7 @@ public interface AnswerRepository extends JpaRepository<Answer, Long> {
             SELECT a FROM Answer a
             JOIN Review r ON a.reviewId = r.id
             WHERE r.reviewGroupId = :reviewGroupId AND a.questionId IN :questionIds
-            ORDER BY r.createdAt DESC
+            ORDER BY r.createdAt DESC, r.id DESC
             LIMIT :limit
             """)
     List<Answer> findReceivedAnswersByQuestionIds(long reviewGroupId, Collection<Long> questionIds, int limit);