pkgs/network-graphs: don't use callPackage as it breaks the flake

nix/pkgs/default.nix

@@ -25,7 +25,7 @@ let
     ) (builtins.attrNames config.site.hosts)
   );
 
-  network-graphs = pkgs.callPackage ./network-graphs.nix { inherit config; };
+  network-graphs = import ./network-graphs.nix { inherit config pkgs; };
 
   mkRootfs = hostName:
     self.nixosConfigurations.${hostName}.config.system.build.toplevel;

nix/pkgs/network-graphs.nix

@@ -1,5 +1,7 @@
-{ lib, config, runCommand, graphviz, ... }:
+{ config, pkgs, ... }:
 let
+  inherit (pkgs) lib runCommand graphviz;
+
   netColor = net:
     if net == "core"
     then "grey"