Application settings from the database are currently cached locally in
the thread for a full minute after the changes are made. That means if
an administrator attempts to change the default storages in the admin
page, it might take up to a full minute for those changes to take
effect.

Since we don't have a great cache invalidation strategy for local caches
yet, the simplest approach to solving this problem would be to expire
the local application setting cache whenever we create a snippet. This
causes every snippet creation to make an additional SELECT call for
`application_settings`.