closes https://linear.app/tryghost/issue/ENG-721
ref https://linear.app/tryghost/issue/ENG-708
Comments-UI loads `/ghost/admin-frame/` in an iframe to check if a Staff User is authenticated in order to show moderation options. That iframe request loads a HTML page which in turn contains a script that fires off an API request that attempts to fetch the logged-in user details, resulting in a 403 "error" showing up when not authenticated. In the vast majority of cases there will be no staff user authenticated so lots of extra requests and "errors" are seen unnecessarily.
- adjusted the `/ghost/auth-frame/` endpoint to check if the request contains an Admin session cookie
- if it does, continue as before with rendering the HTML page so the script is loaded
- if it doesn't, return an empty 204 response avoiding the script request and subsequent 403-generating API request
- eliminates the 403 error being generated for all typical visitor traffic, the error should only be seen when an Admin was previously logged in but their cookie is no longer valid (either from logging out, or going past the 6month validity period)
closes ENG-711
When an Admin is authenticated in Comments-UI we only add moderation options to the displayed comments so we don't need to pre-emptively load the `admin-auth` iframe and make the `/ghost/api/admin/users/me/` request until some comments are actually visible.
- used `state.comments.length` property to defer rendering of the admin auth frame until comments have been fetched (after box is scrolled into view) and the count is > 0
refs https://github.com/TryGhost/Product/issues/3504
- When you are logged in as an admin, but not as a member, no buttons
showed (discovered in new e2e tests)
- Added E2E tests for admin actions
