The `use_helpers` method was added in ViewComponent 3.8.0, and it's
included by default in all components since version 3.11.0.
Note we sometimes delegated the `can?` method to the controller instead
of the helpers, for no particularly reason. We're unifying that code as
well.
We were using the same logic six times regarding when we should show a
"participation not allowed" message. Since we're going to change the
current behavior, we're unifying the logic in one place so the changes
will be easier.