Only validate project visibility when it has changed
On GitLab.com, there are hundreds of projects that have visibility levels that are inconsistent with the fork or group settings. Most likely, this happened during a GitLab project import because the validation was bypassed. Attempting to migrate these projects to hashed storage fails even though the migration doesn't touch the visibility settings. Skipping the visibility validation allows the migration to go through.
Closes #55881 (closed)