Update interfaces/payment-request.idl (#12440)

Copied by https://github.com/foolip/wpt-idl-importer from:
https://github.com/tidoust/reffy-reports/blob/f14a522/whatwg/idl/payment-request.idl
diff --git a/interfaces/payment-request.idl b/interfaces/payment-request.idl
index 1018ecc..3717d79 100644
--- a/interfaces/payment-request.idl
+++ b/interfaces/payment-request.idl
@@ -1,7 +1,7 @@
 // GENERATED CONTENT - DO NOT EDIT
-// Content of this file was automatically extracted from the
-// "Payment Request API" spec.
-// See: https://w3c.github.io/payment-request/
+// Content was automatically extracted by Reffy into reffy-reports
+// (https://github.com/tidoust/reffy-reports)
+// Source: Payment Request API (https://w3c.github.io/payment-request/)
 
 [Constructor(sequence<PaymentMethodData> methodData, PaymentDetailsInit details, optional PaymentOptions options),
 SecureContext, Exposed=Window]
@@ -167,6 +167,8 @@
 dictionary PaymentValidationErrors {
   PayerErrorFields payer;
   AddressErrors shippingAddress;
+  DOMString error;
+  object paymentMethod;
 };
 
 dictionary PayerErrorFields {