chore: update Nix scripts to at least build GUI client (#5423)

I tried to run the GUI client on my system but I think my glibc version
is too recent (2.38) and thus, it crashes after clicking on "Login".

These changes to the Nix script are necessary to at least build the
client.

scripts/nix/flake.nix

@@ -6,7 +6,7 @@
     rust-overlay.url = "github:oxalica/rust-overlay";
   };
 
-  outputs = { self, nixpkgs, flake-utils, rust-overlay, ... } @ inputs:
+  outputs = { nixpkgs, flake-utils, rust-overlay, ... } @ inputs:
     flake-utils.lib.eachDefaultSystem
       (
         system:
@@ -34,6 +34,7 @@
             dbus
             openssl_3
             librsvg
+            libappindicator-gtk3
           ];
 
           packages = with pkgs; [
@@ -47,11 +48,12 @@
             libsoup
             webkitgtk
             librsvg
-            libappindicator-gtk3
+            gnome.zenity
+            desktop-file-utils
           ];
 
           mkShellWithRustVersion = rustVersion: pkgs.mkShell {
-            packages = [ pkgs.cargo-tauri pkgs.iptables cargo-udeps ];
+            packages = [ pkgs.cargo-tauri pkgs.iptables pkgs.nodePackages.pnpm cargo-udeps ];
             buildInputs = rustVersion ++ packages;
             name = "rust-env";
             src = ../../rust;