fix: 미션 기록 생성 raisePet 처리

src/main/java/com/depromeet/stonebed/domain/missionRecord/application/MissionRecordService.java

@@ -85,7 +85,9 @@ public void saveMission(Long missionId, String content) {
                 findMissionHistoryByIdAndRaisePet(missionId, mission.getRaisePet());
 
         MissionRecord missionRecord =
-                MissionRecord.createMissionRecord(content, member, missionHistory);
+                missionRecordRepository
+                        .findByMemberAndMissionHistory(member, missionHistory)
+                        .orElseThrow(() -> new CustomException(ErrorCode.MISSION_RECORD_NOT_FOUND));
 
         missionRecord.updateContent(content);