Vacancies not being updated correctly when they're library roles

[rgoj]

Problem

When a library role is listed as a vacancy, updating the role in the list of library roles doesn't update the vacancies (but does correctly update the role for all holders as expected).

Instructions for reproducing

Please describe steps we'll need to take to reproduce the problem you're seeing, e.g.

1. Create a library role
2. Add it to a circle as a vacancy
3. Go to the directory
4. Change the name of the role in the list of library roles
5. Go to the list of vacancies...
6. ...and confirm that the name hasn't changed there
7. ...nor in the circle in which the vacancy lives if you go back to the map view.

Expected behaviour

Updating the name of a library role should update it in the list of vacancies too.

[rgoj]

Identified while doing thorough testing for new side panels... but this seems to have been already live in production for a long while, so not tackling it now.