refactor: clean up scripts

Tidy up the script logic and deduplicate it a bit.

scripts/audiomenu/package.nix

@@ -1,8 +1,4 @@
-{
+{ lib, rustPlatform, cleanRustSrc }:
-  lib,
-  rustPlatform,
-  cleanRustSrc,
-}:
 let
   cargoToml = builtins.fromTOML (builtins.readFile ./Cargo.toml);
   inherit (cargoToml.package) name version description;

scripts/jpassmenu/package.nix

@@ -1,8 +1,4 @@
-{
+{ lib, rustPlatform, cleanRustSrc }:
-  lib,
-  rustPlatform,
-  cleanRustSrc,
-}:
 let
   cargoToml = builtins.fromTOML (builtins.readFile ./Cargo.toml);
   inherit (cargoToml.package) name version description;