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.
https://community.ui.com/releases/UniFi-Network-Application-7-0-20/3e4a4099-c063-42f6-8e21-5fb2c99fcea9 Since that's a release candidate, unifiLTS remains unchanged.