Add terms to link selection on media page

On the media page, media can be attached using the `Attach` link. Although a media can be attached from inside a taxonomy term page on backend, these terms can't be selected from the attach popup on the media page.

Start from the media page's Attach link and inspect the attach popup, then compare its available term selection with the attachment flow from a taxonomy term page. The work is done when terms can be selected from the media-page popup in the same relevant cases supported by the taxonomy term page.

Written by the indexing model from the issue text.