RHOAIENG-17006: chore(pyproject.toml): migrate test dependencies from poetry to uv

[jiridanek]

https://issues.redhat.com/browse/RHOAIENG-17006

Description

Good first step to unify everything on uv if we are later going to migrate the notebook images from Pipenv to uv.

How Has This Been Tested?

• https://github.com/jiridanek/notebooks/actions/runs/14292796025

Merge criteria:

• The commits are squashed in a cohesive manner and have meaningful messages.
• Testing instructions have been added in the PR body (for PRs involving changes that are not immediately obvious).
• The developer has manually tested the changes and verified that the changes work

[jstourac]

LGTM in general, but we should either link this with some tracking issue or provide some explanation and motivation why we are doing this change so we know in the future.

[jiridanek]

Addressed the review comments, thanks

/approve

[openshift-ci]

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