community/py3-joblib: fix de-vendor
I'm not sure this is enough, but a lot of aports are failing to rebuild now with
/usr/lib/python3.12/site-packages/joblib/_utils.py:11: in <module>
from .externals.loky.process_executor import _ExceptionWithTraceback
E ModuleNotFoundError: No module named 'joblib.externals'