UUID for CallbackContext

[FrancoisPgm]

Add a UUID for the callback contexts, the same id is shared through the whole task tree.

I also added a sanity test for the subcontext method, and in order to check the propagation of the uuid in the task tree I updated the _make_task_tree function in the tests to use _from_parent instead of _from_estimator.

[github-actions]

❌ Linting issues

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cython-lint

cython-lint detected issues. Please fix them locally and push the changes. Here you can see the detected issues. Note that the installed cython-lint version is cython-lint=0.18.1.

/home/runner/work/scikit-learn/scikit-learn/sklearn/cluster/_hdbscan/_tree.pyx:786:19: unnecessary set + generator (just use a set comprehension)

_{Generated for commit: f0a5c91. Link to the linter CI: here}