fix: downgrade jupyterlab to 3.6.6

[thesuperzapper]

Follow up to #7357

This PR downgrades JupyterLab to 3.6.6 and Jupyter Notebooks to 6.5.6.

This is to ensure compatibility with JupyterLab extensions which have not supported JupyterLab 4.0 yet.

I have also re-added the jupyterlab-git extension, as this was one of the plugins that did not support 4.0.

Finally, I have updated the kfp version to 2.4.0, as this version fixes a bug uncovered in Kubeflow 1.8.0-rc.4.

[thesuperzapper]

/assign @DnPlas

[thesuperzapper]

@DnPlas I am going to self-approve here, so you can LGTM to merge it, then wait for the builds before cherry-picking into the release-1.8 branch.

/approve

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[DnPlas]

Thanks @thesuperzapper , should we only change the jupyterlab related packages? I think we should not touch other packages, specially kfp.

[thesuperzapper]

@DnPlas the KFP packages were part of the fix found in testing for Kubeflow 1.8.0-rc.4, so it would be a bit crazy to ship a known broken version of the kfp package?

Here is the changelog for the KFP package: https://github.com/kubeflow/pipelines/blob/master/sdk/RELEASE.md

Also, the other changes are to ensure that conda/pip does not randomly update to the latest JupyterLab (which I was experiencing in testing).

[DnPlas]

/lgtm