Fix delete users follow with job

[Stef-Rousset]

:tophat: What? Why?

Update the delete of private users follow after review from decidim

:pushpin: Related Issues

• Related to this PR on decidim => https://github.com/decidim/decidim/pull/12878

Testing

1. As an admin, edit an assembly and make it private and non transparent (in the Visibility tab)
2. If there is no meeting, add a meeting component to it
3. Invite "user@example.org" as a private user of this assembly
4. As a user, access to the private assembly and click on the follow button
5. Go to the meeting inside assembly and follow it
6. As an admin, delete the private user "user@example.org"
7. As a user, check that you can’t access to the private assembly anymore
8. As an admin, add again "user@example.org" as a private user
9. As a user, go to the assembly and see that your follow has been deleted
10. As a user, go to the meeting and see that your follow has also been deleted

:clipboard: Subtasks

• [x] Add CHANGELOG entry
• [ ] If there's a new public field, add it to GraphQL API
• [ ] Add documentation regarding the feature
• [ ] Add/modify seeds
• [ X] Add tests
• [ ] Another subtask

[Stef-Rousset]

The failing tests are linked to known problem with chromedriver...

In the changes suggested by decidim reviewer, this one "children_follows_to_delete.destroy_all" wasn't possible because children_follows_to_delete is an array and not an active record relation.