Request Accessible Format form generation over-complex

[KludgeKML]

There's code in the helper for request accessible format that makes the html for for radio button with concealed option from an array in the localisation file. This is hard to test individually (because it contains optional rendering calls in a helper), and is just probably not very idiomatic for rails (this should be nested partials really).

https://github.com/alphagov/feedback/pull/1363/files#diff-6a9293f5dfa8d14e139688969ab5bb3fe70321dddcd67151af4b1352c9422d9aR16-R48

Tech-debt issuse to reduce this to simpler nested partials after release.