gs-loading-page: Shorten the loading status string

The design for the pages in gnome-software aims for slightly shorter
‘big’ status strings across the application.

Shorten this to make it take less space, while being just as useful.

Suggested by Tobias Bernard.

Signed-off-by: Philip Withnall <pwithnall@endlessos.org>
3 jobs for shorten-loading-string in 2 minutes and 36 seconds (queued for 36 seconds)