Since we removed the `best_in_place` gem, this method doesn't exist
anymore. We're replacing it with what the method actually does.
Note the test doesn't check the poll is correctly updated. We could add
a `visit proposal_dashboard_polls_path(proposal)` before checking the
"Show results" field, but then we would enter a race condition between
this request and the AJAX request. A proper solution would be to provide
actual feedback to the user so they know the poll has been updated, and
then checking that feedback is present in the tests.