restructure `Samsung Pay` connector wallet details

[ShankarSinghC]

We need to restructure the Samsung Pay session token data stored in the connector wallet details as going forward we will add support for samsung pay payments with hyperswitch credentials. Then the samsung pay payment can be done using either merchant's credentials or hyperswitch's credentials. If it is merchant's credentials, it needs to be provided in the time of the merchant connector account creation.

But when it comes to hyperswitch's credentials flow, merchant will provide only merchant specific business information (like merchant name that should be displayed to customer during the payment and merchant's business country). Whereas the private key or the required Samsung Pay certificates for the decryption will reside in the application env.

"connector_wallets_details": {
        "samsung_pay": {
            "merchant_credentials": {
                "service_id": "samsung pay service id",
                "merchant_display_name": "merchant name",
                "merchant_business_country": "IN",
                "allowed_brands": [
                    "visa",
                    "masterCard",
                    "amex",
                    "discover"
                ]
            }
        }

"connector_wallets_details": {
        "samsung_pay": {
            "application_credentials": {
                "merchant_display_name": "merchant name",
                "merchant_business_country": "IN",
                "allowed_brands": [
                    "visa",
                    "masterCard",
                    "amex",
                    "discover"
                ]
            }
        }