support updated kubespawner

[Adam-D-Lewis]

Reference Issues or PRs

Necessary changes to support Kubespawner >= 5.0.0
Should be merged simultaneously with nebari-dev/nebari-docker-images#194

What does this implement/fix?

Put a x in the boxes that apply

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds a feature)
• Breaking change (fix or feature that would cause existing features not to work as expected)
• Documentation Update
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no API changes)
• Build related changes
• Other (please describe): Update dependencies

Testing

• Did you test the pull request locally?
• Did you add new tests?

How to test this PR?

When using the quay.io/nebari/nebari-jupyterhub:jhub-fancy-profiles-df68a39-20250204 for my jupyterhub image I got errors when loading the profile_list of servers to start up, but this PR resolves them, and I can now start a server successfully with Kubespawner version 6.2.

Any other comments?

[Adam-D-Lewis]

The behavior of Kubespawner changed in v5 so kubespawner_override's default behavior is merge instead of replace now so I'm now simplifing this part.
reference: https://jupyterhub-kubespawner.readthedocs.io/en/latest/changelog.html#id24

[Adam-D-Lewis]

flyby: tornado coroutine to native coroutine

[Adam-D-Lewis]

Failing tests should be able to be rerun. I'm seeing Github rate-limiter failed the request. Either authenticate or wait a couple of minutes. in failing test output.

[Adam-D-Lewis]

"Local Integration Tests" will fail until nebari-dev/nebari-docker-images#194 is merged

[Adam-D-Lewis]

I tested this locally and Local Integration tests passed fine. I changed the jupyterhub image to the one created by the CI in nebari-dev/nebari-docker-images#194 in 5829038. We should revert 5829038 prior to merging, but it'll show reviewers that the tests pass first.