Deleting users with a lot of records can lead to orphans

[pixeldesu]

Steps to reproduce the problem

1. A (large) user deletes themselves

Expected behaviour

Nothing impacts other users.

Actual behaviour

Some user profiles and home/timeline pages break.

Detailed description

This happens because not all relations seem to be deleted properly. Prevalent with users that have a lot of records on them.

I'm not exactly sure what's the reason for this, we don't have any error logs or failures from Sidekiq and the likes that back up that the async destruction jobs outright fail or something (but we should maybe check that).

I assume that something with our relation chains is broken. I don't really find documentation on that, but maybe we need to adjust dependent: destroys down the line to also be async to not cause hickups or something like that.

Specifications

Retrospring 2024.0310.2