feat(nix): add gnome-remote-desktop and freerdp to overlay

- Included `gnome-remote-desktop` and `freerdp` in the unstable overlay for additional remote desktop functionality.
- Removed the `at-spi2-core` override to simplify the configuration.

overlays/mods/default.nix

@@ -5,10 +5,4 @@ final: prev: {
       ./gnome-console-Add-image-and-file-path-pasting-support-for.patch
     ];
   });
-  at-spi2-core = prev.at-spi2-core.overrideAttrs (oldAttrs: {
-    postInstall = (oldAttrs.postInstall or "") + ''
-      substituteInPlace $out/etc/xdg/Xwayland-session.d/00-at-spi \
-        --replace-fail 'exec xprop' 'exec ${final.xorg.xprop}/bin/xprop'
-    '';
-  });
 }