In make_api_response, empty lists were not JSONized because they were
mistakenly detected as a None, which caused these empty lists to be
passed to urlize_links_and_mails, which expects strings.
It caused a TypeError when calling re.sub() on it, which was catched
so it still returned a result (and a correct one, since empty lists
don't need substitution).
This commit removes the catch workaround and always passes the right
Resolves Sentry issue SWH-WEBAPP-H1