Code review comment for ~raharper/curtin:fix/curtainer-dont-wait-for-snap

Thanks! The Groovy minimal images are here:

https://cloud-images.ubuntu.com/minimal/daily/groovy/

so I we can use them in CI.

I think there's a better way ignore the snapd.seeded service:

  lxc init ubuntu:focal test-f
  lxc file push /dev/null test-f/etc/systemd/system/snapd.seeded.service
  lxc start test-f

This will mask the service and prevent it from running at all, which is IMHO better than stopping it. For even better performance we could fully mask snapd.service instead, which also causes snapd.seeded.service to terminate immediately.