small fixes for single payout and big chunck for multiple payouts

frontend/pshared/lib/data/dto/payment/payment.dart

@@ -13,6 +13,8 @@ class PaymentDTO {
   final String? failureCode;
   final String? failureReason;
   final PaymentQuoteDTO? lastQuote;
+  final Map<String, String>? metadata;
+  final String? createdAt;
 
   const PaymentDTO({
     this.paymentRef,
@@ -21,6 +23,8 @@ class PaymentDTO {
     this.failureCode,
     this.failureReason,
     this.lastQuote,
+    this.metadata,
+    this.createdAt,
   });
 
   factory PaymentDTO.fromJson(Map<String, dynamic> json) => _$PaymentDTOFromJson(json);