Hide all issues made by shadow banned users

Release notes

Problem to solve

Malicious actors create many issues in public projects/groups for spam. We need a way to be able to hide their issues until they can be reviewed and deemed safe. Today, the only thing that can be done is Block the user which prevents them from creating more issues. Their issues can be deleted but once they are there's no way to bring them back.

Proposal

Allow issues to be hidden when a user is shadow banned. If a user is unbanned, then their issues should be visible again. Issues should still be visible to admins since they'll likely be going through the activity and deleting any offending content.