feat: add locales for user search in promo offer sending

- Add searchUserPlaceholder, noUsersFound, hasSubscription keys
- Support all 4 languages: en, ru, zh, fa
- Remove fallback strings from component

src/locales/ru.json

@@ -2328,6 +2328,9 @@
         "segment": "Сегмент",
         "user": "Пользователь",
         "userIdPlaceholder": "Telegram ID или User ID",
+        "searchUserPlaceholder": "Поиск по имени, username или Telegram ID...",
+        "noUsersFound": "Пользователи не найдены",
+        "hasSubscription": "Подп",
         "preview": "Предпросмотр",
         "sending": "Отправка...",
         "sendButton": "Отправить"