cinnamon.cinnamon-gsettings-overrides: Add gsettings-desktop-schemas

To override org.gnome.desktop.interface.

pkgs/desktops/cinnamon/cinnamon-gsettings-overrides/default.nix

···
     cinnamon-settings-daemon
     cinnamon-common
     gnome.gnome-terminal
+    gsettings-desktop-schemas
     gtk3
   ] ++ extraGSettingsOverridePackages;