feat(payment): integrate TwentyCard payment option and enhance checkout flow

- Added a new payment method for TwentyCard in the checkout process, allowing users to select it alongside direct payment options.
- Implemented the logic for processing TwentyCard payments, including user feedback and dialog interactions for payment confirmation.
- Updated the appsettings files to include configuration for the new payment method.
- Enhanced the user interface in the PackagePurchaseDialog to reflect the new payment option and its requirements.

These changes improve the payment flexibility in the checkout process, providing users with additional options for completing their transactions.

src/FrontOffice.Main/appsettings.json

@@ -6,6 +6,9 @@
   },
   "GwUrl": "https://cms.se.kbs1.ir",
   "DownloadUrl": "",
+  "TwentyCard": {
+    "CreditPortalUrl": "https://20card.ir"
+  },
   "EncryptionSettings": {
     "Key": "kmcQ3XTmH4mrdh8VHziuscyf8LLYjG//Kyni81nH/0E=",
     "IV": "1wyF3Tt142MOkCpIyCxh/g=="