Fix 500 error accessing restricted visibility levels
!22522 (merged) introduced a
regression that caused a 500 error if the
application_settings.restricted_visibility_levels column were
Since there is no NOT NULL constraint, there's no guarantee that it is
populated with the proper serialized YAML data.
To fix this specific problem, we can account for
nil values, but we
should fix this at the database level.
Closes #215552 (closed)