TF-3454 Integration test download all attachments as ZIP

integration_test/robots/email_robot.dart

@@ -1,4 +1,5 @@
 import 'package:flutter_test/flutter_test.dart';
+import 'package:tmail_ui_user/main/localizations/app_localizations.dart';
 
 import '../base/core_robot.dart';
 
@@ -9,4 +10,9 @@ class EmailRobot extends CoreRobot {
     await $(#forward_email_button).tap();
     await $.pump(const Duration(seconds: 2));
   }
+
+  Future<void> tapDownloadAllButton() async {
+    await $(AppLocalizations().downloadAll).tap();
+    await $.pumpAndSettle();
+  }
 }