[FEA] Include Dask Coverage for Notebooks

**Is your feature request related to a problem? Please describe.**

cuDF currently has at least one Dask-related notebook, but CI does not appear to execute it as part of notebook test coverage. This leaves Dask notebook examples vulnerable to regressions that may not be caught before merge.

**Describe the solution you'd like**

Add CI coverage for Dask notebooks, starting with:

`docs/cudf/source/user_guide/10min.ipynb`

The CI job should execute the notebook and fail if the notebook errors. Ideally, the implementation should also provide a reusable framework so future Dask notebooks can be added to the same test path easily.

**Describe alternatives you've considered**

An alternative would be to rely on existing documentation or notebook checks, but those do not currently appear to cover Dask notebook execution specifically.

**Additional context**

As of 2026-05-18, the only notebook in the repository that appears to use Dask is:

`docs/cudf/source/user_guide/10min.ipynb`

This notebook imports and uses `dask_cudf`, so it may require a CI environment with the appropriate Dask/cuDF dependencies available.