Fix Shared Parental Leave visualization

2 nodes with an unrecognised question type  (amount leave) were throwing off the balance of question to title and causing a `nil` error on the missing question.

I'm not familiar enough with the content to know the state of this question, so for now i've marked it as `TODO` and made it an `h2`, so it's still visible in flow as a reminder and the content is still present (the question renders as markdown, as it did before).