Deny disk access even from sidekiq workers if updates on legacy storage are disabled

https://gitlab.com/gitlab-org/gitlab/blob/8ba3ee02bf26d12c7b760d8bcd8af4506273a3bb/lib/gitlab/pages/settings.rb#L8 - we currently raise error only for web-nodes. We should do it updates on legacy storage are disabled.

This probably needs to broken down more.