Dashboards: Fix scroll position not being restored when leaving panel edit (#83787)

* Dashboards: Fix scroll position not being restored when leaving panel edit view

* remove mock from tests

* remove console log

* Remove my debugging stuff, and don't render grid if width is 0

* remove old comment (but retain old, probably unneeded css)

* rename ref

* fix it not actually working anymore!!!

* add e2e tests

* jsonnet, i guess

e2e/dashboards-suite/general-dashboards.spec.ts

@@ -0,0 +1,33 @@
+import { e2e } from '../utils';
+
+const PAGE_UNDER_TEST = 'edediimbjhdz4b/a-tall-dashboard';
+
+describe('Dashboards', () => {
+  beforeEach(() => {
+    e2e.flows.login(Cypress.env('USERNAME'), Cypress.env('PASSWORD'));
+  });
+
+  it('should restore scroll position', () => {
+    e2e.flows.openDashboard({ uid: PAGE_UNDER_TEST });
+    e2e.components.Panels.Panel.title('Panel #1').should('be.visible');
+
+    // scroll to the bottom
+    e2e.pages.Dashboard.DashNav.navV2()
+      .parent()
+      .parent() // Note, this will probably fail when we change the custom scrollbars
+      .scrollTo('bottom', {
+        timeout: 5 * 1000,
+      });
+
+    // The last panel should be visible...
+    e2e.components.Panels.Panel.title('Panel #50').should('be.visible');
+
+    // Then we open and close the panel editor
+    e2e.components.Panels.Panel.menu('Panel #50').click({ force: true }); // it only shows on hover
+    e2e.components.Panels.Panel.menuItems('Edit').click();
+    e2e.components.PanelEditor.applyButton().click();
+
+    // And the last panel should still be visible!
+    e2e.components.Panels.Panel.title('Panel #50').should('be.visible');
+  });
+});