Dashboards/E2E: Add test validating panel duplication (#105663)

* Dashboards/E2E: Add test validating panel duplication

* Validate duplicates remain after save/reload

e2e/dashboard-new-layouts/dashboard-duplicate-panel.spec.ts

@@ -0,0 +1,30 @@
+import { e2e } from '../utils';
+
+import { flows } from './dashboard-edit-flows';
+
+describe('Dashboard panels', () => {
+  beforeEach(() => {
+    e2e.flows.login(Cypress.env('USERNAME'), Cypress.env('PASSWORD'));
+  });
+
+  it('can duplicate a panel', () => {
+    e2e.flows.scenes.importV2Dashboard({ title: 'Paste tab' });
+
+    e2e.flows.scenes.toggleEditMode();
+    const panelTitle = 'Unique';
+    flows.changePanelTitle('New panel', panelTitle);
+
+    e2e.components.Panels.Panel.title(panelTitle).should('have.length', 1);
+
+    e2e.components.Panels.Panel.menu(panelTitle).click({ force: true });
+    e2e.components.Panels.Panel.menuItems('More...').trigger('mouseover');
+    e2e.components.Panels.Panel.menuItems('Duplicate').click();
+
+    e2e.components.Panels.Panel.title(panelTitle).should('have.length', 2);
+
+    // Save, reload, and ensure duplicate has persisted
+    e2e.flows.scenes.saveDashboard();
+    cy.reload();
+    e2e.components.Panels.Panel.title(panelTitle).should('have.length', 2);
+  });
+});