Test hang (test_cosmo_docs_model_classy)

[cmbant]

Even on py3.13 still getting these. Sometimes it works but slow

https://github.com/CobayaSampler/cobaya/actions/runs/19430053741/job/55586550168

Sometimes hangs

https://github.com/CobayaSampler/cobaya/actions/runs/19497390038/job/55802852192