Replace placeholder guest with existing phone guest

src/main/kotlin/com/android/trisolarisserver/repo/GuestVehicleRepo.kt

@@ -8,4 +8,5 @@ interface GuestVehicleRepo : JpaRepository<GuestVehicle, UUID> {
     fun findByPropertyIdAndVehicleNumberIgnoreCase(propertyId: UUID, vehicleNumber: String): GuestVehicle?
     fun findByGuestIdIn(guestIds: List<UUID>): List<GuestVehicle>
     fun existsByPropertyIdAndVehicleNumberIgnoreCase(propertyId: UUID, vehicleNumber: String): Boolean
+    fun existsByGuestId(guestId: UUID): Boolean
 }