TF-4301 Add E2E tests for label creation and tagging from email view

integration_test/robots/labels/add_label_modal_robot.dart

@@ -0,0 +1,11 @@
+import 'package:flutter_test/flutter_test.dart';
+
+import '../../base/core_robot.dart';
+
+class AddLabelModalRobot extends CoreRobot {
+  AddLabelModalRobot(super.$);
+
+  Future<void> tapCreateANewLabel() async {
+    await $(#create_a_new_label_button).tap();
+  }
+}

integration_test/robots/labels/label_robot.dart

@@ -15,4 +15,10 @@ class LabelRobot extends CoreRobot {
   Future<void> tapCreateNewLabelButton() async {
     await $(#labels_bar_widget_add_new_label_button).tap();
   }
+
+  Future<void> openLabelByName(String name) async {
+    final item = $(LabelListItem).$(name);
+    await $.scrollUntilVisible(finder: item);
+    await item.tap();
+  }
 }