mate.mate-applets: Add missing mate-desktop

Since we do `g_settings_new ("org.mate.lockdown")`, we will
need to pass this to the wrapper.

Fixes https://github.com/NixOS/nixpkgs/issues/271315.

pkgs/desktops/mate/mate-applets/default.nix

@@ -15,6 +15,7 @@
 , libgtop
 , libxml2
 , libnotify
+, mate-desktop
 , mate-panel
 , polkit
 , upower
@@ -53,6 +54,7 @@ stdenv.mkDerivation rec {
     libnotify
     libwnck
     libxml2
+    mate-desktop # for org.mate.lockdown
     mate-panel
     polkit
     upower