Chore: Low hanging a11y fruits (#37783)

* aria-label disallowed on header element

* A11y issues for Getting Started and panel header

* Add unique identifier to search navigation

* Add dashboard header markup

* Fix news panel low hanging fruits

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

@@ -44,7 +44,7 @@ export const Components = {
   },
   Panels: {
     Panel: {
-      title: (title: string) => `Panel header ${title}`,
+      title: (title: string) => `data-testid Panel header ${title}`,
       headerItems: (item: string) => `Panel header item ${item}`,
       containerByTitle: (title: string) => `${title} panel`,
       headerCornerInfo: (mode: string) => `Panel header ${mode}`,