web: improve testability (#6952)

web/improve testability

This is a trio of small hacks that allow the E2E tests to find several components
on the page while the test is running:

- Add a `data-managed-for` field to SearchSelect's positioned elements. If a search
  has a `name` field, it will be reflected here, allowing tests to find specific
  instances of the dropdown elements.
- Add a forwarder to the search select wrappers we use for our SearchSelect.
- Added aria details to the UserLibrary header to make it easy to identify.

web/src/user/LibraryPage/LibraryPageImpl.ts

@@ -136,7 +136,9 @@ export class LibraryPage extends AKElement {
     render() {
         return html`<main role="main" class="pf-c-page__main" tabindex="-1" id="main-content">
             <div class="pf-c-content header">
-                <h1>${msg("My applications")}</h1>
+                <h1 role="heading" aria-level="1" id="library-page-title">
+                    ${msg("My applications")}
+                </h1>
                 ${this.uiConfig.searchEnabled ? this.renderSearch() : html``}
             </div>
             <section class="pf-c-page__main-section">