Add Page title to HST comments

Right now, we display the page title in the right side panel for the Edit page unavailable component. In the previous functionality, the sitemap was loaded on page init so it could get the page title from the sitemap list. Now, we load sitemap items only when the sitemap is open.

Acceptance criteria 

The property "title" should be added to HST comments with the following condition:

title = currentSitemapItem.pageTitle || currentSitemapItem.name;