Provide "access" to notifications for UI tests.

Context

notifications app is a content app, tho it is added to the group /modules/ui-admincentral/config/appLauncherLayout/hiddenApps, hence it cannot be opened via find bar.

There is an always available "box" on the Uadmin with a link to open the app and the number of notifications.

Required functions, methods:

• Open the notifications app
  (which I expect to work as every content app once it is opened)

• Providing the number of "new" (not yet visited) notifications