Dashboards/E2E: Add tests for grouping and ungrouping into rows and tabs (#105315)

* add e2e for grouping into tabs and rows

* enable kubernetesDashboards feature toggle for e2e tests

* remove unnecessary kubernetesDashboard feature flag enablement

e2e/utils/flows/scenes/saveDashboard.ts

@@ -0,0 +1,8 @@
+import { e2e } from '../../index';
+
+export const saveDashboard = () => {
+  e2e.components.NavToolbar.editDashboard.saveButton().click();
+
+  e2e.components.Drawer.DashboardSaveDrawer.saveButton().click();
+  e2e.flows.assertSuccessNotification();
+};