ci: Build gsettings-desktop-schemas from git

Needed for accent-color support in gnome-shell.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/3826>

.gitlab-ci.yml

@@ -87,7 +87,7 @@ variables:
     - .skip-git-clone
   variables:
     FDO_DISTRIBUTION_VERSION: 40
-    BASE_TAG: '2024-06-11.0'
+    BASE_TAG: '2024-06-19.1'
     MUTTER_USER: 'meta-user'
     FDO_DISTRIBUTION_PACKAGES:
       asciidoc
@@ -140,6 +140,10 @@ variables:
         https://gitlab.freedesktop.org/wayland/wayland-protocols.git \
         1.36
 
+      ./.gitlab-ci/install-meson-project.sh \
+        https://gitlab.gnome.org/GNOME/gsettings-desktop-schemas.git \
+        master
+
       rpm -e --nodeps gnome-bluetooth-libs-devel \
                       mutter mutter-devel \
                       gnome-shell \