Revert "add nix-prefetch-source (#21734)"

This reverts commit ca38ef79e9d1530cd32890bf9e4760096f25f048 due its
use of importJSON and external source info files, which is
non-idiomatic.

pkgs/tools/package-management/nix-update-source/default.nix

@@ -1,29 +0,0 @@
-{ lib, pkgs, fetchFromGitHub, python3Packages, nix-prefetch-scripts }:
-python3Packages.buildPythonApplication rec {
-  version = "0.2.1";
-  name = "nix-update-source-${version}";
-  src = fetchFromGitHub {
-    owner = "timbertson";
-    repo = "nix-update-source";
-    rev = "version-${version}";
-    sha256 = "1w3aj0kjp8zhxkzqxnm5srrsqsvrmxhn4sqkr4kjffh61jg8jq8a";
-  };
-  propagatedBuildInputs = [ nix-prefetch-scripts ];
-  passthru = {
-    fetch = path:
-      let
-        fetchers = {
-          # whitelist of allowed fetchers
-          inherit (pkgs) fetchgit fetchurl fetchFromGitHub;
-        };
-        json = lib.importJSON path;
-        fetchFn = builtins.getAttr json.fetch.fn fetchers;
-        src = fetchFn json.fetch.args;
-      in
-      json // { inherit src; };
-  };
-  meta = {
-    description = "Utility to autimate updating of nix derivation sources";
-    maintainers = with lib.maintainers; [ timbertson ];
-  };
-}

pkgs/top-level/all-packages.nix

@@ -17567,8 +17567,6 @@ with pkgs;
     nix-prefetch-zip
     nix-prefetch-scripts;
 
-  nix-update-source = callPackage ../tools/package-management/nix-update-source {};
-
   nix-template-rpm = callPackage ../build-support/templaterpm { inherit (pythonPackages) python toposort; };
 
   nix-repl = callPackage ../tools/package-management/nix-repl { };