i8n과 광고 수정

lib/controllers/detail_screen_controller.dart

@@ -454,7 +454,7 @@ class DetailScreenController extends ChangeNotifier {
     if (adjustedNext.isAfter(originalDateOnly)) {
       AppSnackBar.showInfo(
         context: context,
-        message: '다음 결제 예정일로 저장됨',
+        message: AppLocalizations.of(context).nextBillingDateAdjusted,
       );
     }