TF-4404 Add e2e test for Mail to attendees action on mobile

integration_test/tests/calendar/mail_to_attendees_event_email_test.dart

@@ -0,0 +1,11 @@
+import '../../base/test_base.dart';
+import '../../scenarios/calendar/mail_to_attendees_event_email_scenario.dart';
+
+void main() {
+  TestBase().runPatrolTest(
+    description: 'Should fill subject with reply prefix '
+        'when user taps mail to attendees button '
+        'on calendar event email',
+    scenarioBuilder: ($) => MailToAttendeesEventEmailScenario($),
+  );
+}