nixos/tests/unifi: inherit allowUnfree into test node

mongodb is unfree, so the test won't run without this. we already allow
unfree to grab the unifi packages, so it's not even a big change.

pennae 5dce130d 4ed9534f

Changed files
+2
nixos
tests
+2
nixos/tests/unifi.nix
···
};
nodes.server = {
services.unifi = {
enable = true;
unifiPackage = unifi;
···
};
nodes.server = {
+
nixpkgs.config = config;
+
services.unifi = {
enable = true;
unifiPackage = unifi;