small fixes for single payout and big chunck for multiple payouts

frontend/pshared/lib/data/mapper/payment/quote/quotes.dart

@@ -3,11 +3,10 @@ import 'package:pshared/data/mapper/payment/payment_quote.dart';
 import 'package:pshared/data/mapper/payment/quote/aggregate.dart';
 import 'package:pshared/models/payment/quote/quotes.dart';
 
-
 extension PaymentQuotesDTOMapper on PaymentQuotesDTO {
   PaymentQuotes toDomain({String? idempotencyKey}) => PaymentQuotes(
     quoteRef: quoteRef,
-    idempotencyKey: idempotencyKey,
+    idempotencyKey: idempotencyKey ?? this.idempotencyKey,
     aggregate: aggregate?.toDomain(),
     quotes: quotes?.map((quote) => quote.toDomain()).toList(),
   );
@@ -16,6 +15,7 @@ extension PaymentQuotesDTOMapper on PaymentQuotesDTO {
 extension PaymentQuotesMapper on PaymentQuotes {
   PaymentQuotesDTO toDTO() => PaymentQuotesDTO(
     quoteRef: quoteRef,
+    idempotencyKey: idempotencyKey,
     aggregate: aggregate?.toDTO(),
     quotes: quotes?.map((quote) => quote.toDTO()).toList(),
   );