TF-3707 Add integration test for case empty trash

Signed-off-by: dab246 <tdvu@linagora.com>

integration_test/tests/mailbox/empty_trash_test.dart

@@ -0,0 +1,9 @@
+import '../../base/test_base.dart';
+import '../../scenarios/mailbox/empty_trash_scenario.dart';
+
+void main() {
+  TestBase().runPatrolTest(
+    description: 'Should empty view and hide empty trash banner when empty trash successfully',
+    scenarioBuilder: ($) => EmptyTrashScenario($),
+  );
+}