It’s not either text messages, or emails, or both now – it’s any
combination of the three channels.
This commit adds ‘letters’ as an option on the request to go live page
by changing the radio buttons to a group of checkboxes, so the user can
choose as many or as few as they want.
This commit also does a bunch of housekeeping stuff around the tests for
this page, because they haven’t been touched in quite some time.