`Upload#url` is more likely and can change from time to time. When it
does changes, we don't want to have to look through multiple tables to
ensure that the URLs are all up to date. Instead, we simply associate
uploads properly to `UserProfile` so that it does not have to replicate
the URLs in the table.
This is a regression as a result of 7896c74c2bd161f85c976fcd8468797721df30d9. Most instances would have ran the migrations and some might have run this migration with the incorrect query. Impact of this is small for now but I'm fixing this for correctness purposes.
* Doing it in a post migration was a bad idea
because the migration will fail if the site
is down while trying to download uploads
which points to the instance. This mainly
affects self-hosters using `discourse_docker`
where `./launcher rebuild` will take the
existing container down.
