mashu: Fix phosh not recognizing the volume keys and backlight

hosts/mashu.nix

@@ -50,6 +50,26 @@ in mkHost config {
     };
 
     services.gnome.gnome-settings-daemon.enable = true;
+    systemd.user.services = {
+      gsd-media = {
+        description = "GSD media keys handling";
+        wantedBy = [ "default.target" ];
+        serviceConfig = {
+          Type = "simple";
+          ExecStart = "${pkgs.gnome.gnome-settings-daemon}/libexec/gsd-media-keys";
+          Restart = "always";
+        };
+      };
+      gsd-power = {
+        description = "GSD media keys handling";
+        wantedBy = [ "default.target" ];
+        serviceConfig = {
+          Type = "simple";
+          ExecStart = "${pkgs.gnome.gnome-settings-daemon}/libexec/gsd-power";
+          Restart = "always";
+        };
+      };
+    };
     programs.phosh = {
       enable = true;
       phocConfig = {