bluej: use dpkg instead of manual preUnpackHook

pkgs/applications/editors/bluej/default.nix

···
-{ lib, stdenv, fetchurl, openjdk, glib, wrapGAppsHook, zstd }:
+{ lib, stdenv, fetchurl, openjdk, glib, dpkg, wrapGAppsHook }:
 
 stdenv.mkDerivation rec {
   pname = "bluej";
···
     sha256 = "sha256-sOT86opMa9ytxJlfURIsD06HiP+j+oz3lQ0DqmLV1wE=";
   };
 
-  nativeBuildInputs = [ zstd wrapGAppsHook ];
+  nativeBuildInputs = [ dpkg wrapGAppsHook ];
   buildInputs = [ glib ];
-
-  sourceRoot = ".";
-
-  preUnpack = ''
-    unpackCmdHooks+=(_tryDebData)
-    _tryDebData() {
-      if ! [[ "$1" =~ \.deb$ ]]; then return 1; fi
-      ar xf $src
-      if ! [[ -e data.tar.zst ]]; then return 1; fi
-      unpackFile data.tar.zst
-    }
-  '';
 
   dontWrapGApps = true;