docs(tasks): remove references to removed question-answering pipeline (#44787)
The question-answering pipeline was removed in v5.0.0 per MIGRATION_GUIDE_V5.md.
This updates the non-English task guides to remove usage of pipeline('question-answering')
which no longer exists and would raise:
Unknown task question-answering, available tasks are [...]
The docs now show the direct tokenizer/model approach instead, consistent with
the English version of the guide.
Fixes #44752
Co-authored-by: BillionClaw <billionclaw@users.noreply.github.com>