Remove useless flake configuration

nixos/configuration.nix

@@ -1,7 +1,5 @@
 {
   inputs,
-  lib,
-  config,
   ...
 }:
 {
@@ -29,21 +27,11 @@
     ];
   };
 
-  nix =
-    let
-      flakeInputs = lib.filterAttrs (_: lib.isType "flake") inputs;
-    in
-    {
-      settings = {
-        experimental-features = "nix-command flakes";
-        flake-registry = ""; # Opinionated: disable global registry
-        nix-path = config.nix.nixPath; # Workaround for https://github.com/NixOS/nix/issues/9574
-      };
-      # Opinionated: make flake registry and nix path match flake inputs
-      registry = lib.mapAttrs (_: flake: { inherit flake; }) flakeInputs;
-      nixPath = lib.mapAttrsToList (n: _: "${n}=flake:${n}") flakeInputs;
-      channel.enable = false; # Opinionated: disable channels
+  nix = {
+    settings = {
+      experimental-features = "nix-command flakes";
     };
+  };
 
   networking.hostName = "nixos";
   networking.firewall.enable = true;