nixos/installation-device: use a bigger hammer (#339199)

    nix.settings.trusted-users = [ "nixos" ];

    # Install less voices for speechd to save some space

    services.speechd.package = pkgs.speechd.override {

      mbrola = pkgs.mbrola.override {

        mbrola-voices = pkgs.mbrola-voices.override {

    nixpkgs.overlays = [

      (_: prev: {

        mbrola-voices = prev.mbrola-voices.override {

          # only ship with one voice per language

          languages = [ "*1" ];

        };

      };

    };

      })

    ];

  };

}