Updating a hub from `using profile_list` to `no profile_list` results in `user_options` not being cleanup up from the hub db

[GeorgianaElena]

Bug description

After updating a z2jh hub deployment from having a profileList to spawning directly an image, my spawn failed.

I don't have the hub logs anymore, but this is the log message it printed
https://github.com/jupyterhub/jupyterhub/blob/ab91bdd4732e3840ca6aaf6b8ff713fbd972d436/jupyterhub/handlers/pages.py#L251
before failing to spawn because it couldn't find whatever the default profile option was set on the initial profileList setup.

Upon inspecting the spawners table in the hub db, it looked like user_options still had data related to the initial profile setup:

1|11||{"kubespawner_version": "7.0.0", "pod_name": "jupyter-georgianaelena", "namespace": "staging", "dns_name": "jupyter-georgianaelena.staging.svc.cluster.local"}|||2025-11-19 12:02:13.566780|{"profile": "only-choice", "image": "bnext-nucleus", "resource_allocation": "mem_4_gb"}|

Manually updating the table to emtpy the userdata_options dict unblocked me.

How to reproduce

1. Deploy z2jh hub with profileLists
2. Start a server
3. Re-deploy the same hub, after removing the profileList
4. Try to start a server
5. See error

Expected behaviour

Server spawns

Actual behaviour

Error about profille option not being there.

Your personal set up

Z2JH 4.0.0