fix: 회원의 예약 확정 여부를 확인하는 쿼리에서, 입력된 id가 없으면 예외를 던지는 문제 해결(-> false 반환)

src/main/java/roomescape/reservation/infrastructure/persistence/ReservationRepository.kt

@@ -28,10 +28,16 @@ interface ReservationRepository
     @Query("""
 		SELECT EXISTS (
             SELECT 1
-            FROM ReservationEntity r
+            FROM ReservationEntity r2
-            WHERE r.id = :id
+            WHERE r2.id = :id 
+              AND EXISTS (   
+                  SELECT 1 FROM ReservationEntity r
+                  WHERE r.theme.id = r2.theme.id
+                    AND r.reservationTime.id = r2.reservationTime.id
+                    AND r.date = r2.date
                     AND r.reservationStatus != 'WAITING'
             ) 
+        )
 	""")
     fun isExistConfirmedReservation(@Param("id") reservationId: Long): Boolean