Exception: Namespace cannot be moved, because at least one project has tags in container registry

/cc: @ayufan

-Stan

https://sentry.gitlap.com/gitlab/gitlabcom/issues/5810/

Exception: Namespace cannot be moved, because at least one project has tags in container registry
  app/models/namespace.rb:114:in `move_dir'
    raise Exception.new('Namespace cannot be moved, because at least one project has tags in container registry')
  lib/gitlab/metrics/instrumentation.rb:153:in `move_dir'
    retval   = super
  app/services/groups/update_service.rb:17:in `execute'
    group.save
  lib/gitlab/metrics/instrumentation.rb:153:in `execute'
    retval   = super
  app/controllers/groups_controller.rb:85:in `update'
    if Groups::UpdateService.new(@group, current_user, group_params).execute
...
(132 additional frame(s) were not displayed)