TF-4265 Add integration test for attachment reminder on mobile

integration_test/tests/composer/attachment_reminder_test.dart

@@ -0,0 +1,10 @@
+import '../../base/test_base.dart';
+import '../../scenarios/composer/attachment_reminder_scenario.dart';
+
+void main() {
+  TestBase().runPatrolTest(
+    description:
+        'Should not see attachment reminder when send email with attachment keyword in signature',
+    scenarioBuilder: ($) => AttachmentReminderScenario($),
+  );
+}