To-Do counts might be off due to missing targets

As part of investigating #509515, we found that there is another vector for wrong to-do counts: Stale data.

Screen_Recording_2024-12-16_at_11.19.21_AM

Apparently @laurenbarker (video above) has 4 todos while everything is done. Looking into the production database, it seems like the underlying MRs which the todos are pointing to, have been deleted.

It's still unclear why the todos have not deleted when the underlying Merge Request was.