Enhance TopUpModal styling and update localization files

- Updated button styles in TopUpModal for improved visual feedback during interactions.
- Adjusted modal positioning for better user experience on desktop.
- Added 'paymentMethod' key to localization files for English, Persian, Russian, and Chinese languages, enhancing multi-language support.

src/locales/fa.json

@@ -184,6 +184,7 @@
     "topUp": "شارژ",
     "topUpBalance": "شارژ موجودی",
     "enterAmount": "مقدار را وارد کنید",
+    "paymentMethod": "روش پرداخت",
     "paymentMethods": {
       "yookassa": {
         "name": "YooKassa",