Explicity mark non-visible widgets in GtkBuilder files

GTK+ 4 sets visibility to true by default, so we should explicitly mark those as
non-visible. The visible=True attributes can be removed after migration.
1 job for <span class="ref-name">explicit-invisible</span> in 15 seconds (queued for 13 minutes and 59 seconds)
Status Job ID Name Coverage
  Build
failed #116947
build-gnome-software

00:00:15

 
Name Stage Failure
failed
build-gnome-software Build
Using Docker executor with image fedora:28 ...
Pulling docker image fedora:28 ...
Using docker image sha256:c582c1438f27b3775e2534abc82d14974ecb00c2c53161d05ec73a73d35e1235 for fedora:28 ...
Running on runner-f23948e6-project-601-concurrent-0 via progress.gnome.org...
Cloning repository...
Cloning into '/builds/robert.ancell/gnome-software'...
Checking out 4c7997c0 as explicit-invisible...
fatal: reference is not a tree: 4c7997c0bdbb1c9c1c75376d6ab5cb53c7e2343e
ERROR: Job failed: exit code 1