StoredPaymentMethodDetails doesn't have support for the "subtype" field used by the native TWINT drop-in

[elitalon]

Describe the bug
Deserialisation of a POST /payments request done against a proxy backend ignores the subtype field from the paymentMethod object in the JSON body.

This results in the drop-in integration of TWINT for iOS using a web-based UI instead of the native one.

How to reproduce
Make a POST /payments request with the following JSON body:

{
    "channel": "iOS",
    "amount": {
        "currency": "CHF",
        "value": 0
    },
    "browserInfo": {
        "userAgent": "<redacted>"
    },
    "merchantAccount": "<redacted>",
    "returnUrl": "<redacted>",
    "storePaymentMethod": true,
    "countryCode": "CH",
    "paymentMethod": {
        "type": "twint",
        "subtype": "sdk"
    },
    "shopperLocale": "en_US",
    "shopperReference": "<redacted>",
    "reference": "<redacted>",
    "recurringProcessingModel": "<redacted>",
    "shopperInteraction": "Ecommerce"
}

Expected behavior
The resulting StoredPaymentMethodDetails object stores the value of the subtype JSON field.

Screenshots
Not applicable

Desktop (please complete the following information):

• Java Version: Java 21
• Library Version: 28.2.0

Additional context
This problem was discovered as part of Adyen/adyen-ios#1783.

[jillingk]

Hi @elitalon,

Thanks for reaching out here, we have a fix on the way!

Best, Jilling
Adyen