Changing user groups needs manual holo apply --force

[laerling]

Steps to reproduce

1. Create hologram/holodeck with user who is in a few groups
2. Install said hologram/holodeck
3. Create another hologram which puts the existing user into an additional group:

[[user]]
name = "$name"
groups = [ "some-other-group" ]

4. Install the new hologram

Expected behavior

The user is reprovisioned without user intervention

Observed behavior

holo apply --force is needed to reprovision the user, even though it hasn't been changed manually.