미납금 정산확정일자 null처리

src/main/java/com/oqpo/api/web/dto/response/loanmng/UnpaidMngInfoResponse.java

@@ -81,7 +81,7 @@ public class UnpaidMngInfoResponse {
         return UnpaidMngInfoResponse.builder()
                 .sttlMgntUnqNo(entity.getSttlMgntUnqNo())
                 .sttlReqDt(entity.getSttlReqDt())
-                .sttlDt(entity.getSttlDt())
+                .sttlDt(entity.getSttlDt() == null ? "" : entity.getSttlDt())
                 .brandId(entity.getBrandId())
                 .brandNm(entity.getBrandNm())
                 .storeId(entity.getStoreId())