knot-resolver: allow local networking in Darwin tests

pkgs/by-name/kn/knot-resolver_5/package.nix

@@ -140,6 +140,7 @@ let
       rm -r "$out"/lib/sysusers.d/ # ATM more likely to harm than help
     '';
 
+    __darwinAllowLocalNetworking = true;
     doInstallCheck = with stdenv; hostPlatform == buildPlatform;
     nativeInstallCheckInputs = [
       cmocka

pkgs/by-name/kn/knot-resolver_6/package.nix

@@ -121,6 +121,7 @@ let
       rm -r "$out"/lib/sysusers.d/ # ATM more likely to harm than help
     '';
 
+    __darwinAllowLocalNetworking = true;
     doInstallCheck = with stdenv; hostPlatform == buildPlatform;
     nativeInstallCheckInputs = [
       which