Add Panel: fixes No gap between rows in safari (#35570) (#35661)

* Add Panel: fixes No gap between rows in safari

* removes extra margin from bottom and far right

* fixes frontend test

* make add panel actions accessible and rewrite test using RTL

(cherry picked from commit 6ee2f1fe3e)

Co-authored-by: Uchechukwu Obasi <obasiuche62@gmail.com>

packages/grafana-e2e-selectors/src/selectors/pages.ts

@@ -32,6 +32,8 @@ export const Pages = {
   AddDashboard: {
     url: '/dashboard/new',
     addNewPanel: 'Add new panel',
+    addNewRow: 'Add new row',
+    addNewPanelLibrary: 'Add new panel from panel library',
   },
   Dashboard: {
     url: (uid: string) => `/d/${uid}`,