New endpoint to use failed process elements in a selection

Refs https://gitlab.com/teklia/requests/-/issues/817

We need a new endpoint SelectProcessFailures (or another suitable name you prefer 🤷 ) that takes as input:

• process_id

This endpoint lists all failed elements (using WorkerActivity) and sets them as current user selection for that process corpus. This can only work for finished processes in elements mode.

I'm not sure if this requires an async worker, as this should be a fairly trivial update from select query.