[BUG] Editors removed from Journal Membership are left assigned to their submissions

[danielBingham]

Describe the bug

Describe the bug you encountered. What happened? What did you expect to happen?

When you remove an editor or reviewer from journal membership, they remain assigned to submissions on that journal. We may want different behavior here for reviewers or editors... at least for editors they need to unassigned from submissions when removed from journal membership.

We probably want that behavior for reviewers too.

To Reproduce

Please describe the exact steps required to reproduce the bug.

1. Add a user to a journal.
2. Assign the user to a submission as editor or reviewer.
3. Remove the user from the journal.
4. User will remain assigned.