ci: Replace Cantarell with Adwaita fonts in toolbox image

The default changed, so follow suit. The fonts aren't packaged
in Fedora yet, so use git for now.

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/3639>

.gitlab-ci/build-toolbox-image.sh

@@ -33,7 +33,6 @@ build_container() {
     flatpak-spawn # run host commands
     flatpak # for host apps
     nautilus # FileChooser portal
-    abattis-cantarell-fonts # system font
     gnome-backgrounds # no blank background!
   )
   local debug_packages=(
@@ -54,6 +53,9 @@ build_container() {
   local srcdir=$(realpath $(dirname $0))
   buildah copy --chmod 755 $build_cntr $srcdir/install-meson-project.sh /usr/libexec
 
+  buildah run $build_cntr /usr/libexec/install-meson-project.sh \
+    https://gitlab.gnome.org/GNOME/adwaita-fonts.git main
+
   # include convenience script for updating mutter dependency
   local update_mutter=$(mktemp)
   cat > $update_mutter <<-EOF