Fix crash on nil/non-url array by checking before we call the swift method.
Fix crash on nil/non-url array by checking before we call the swift method.

Reject any non-NSUrls
Do not call with a nil/empty array

https://rink.hockeyapp.net/manage/apps/152731/app_versions/68/crash_reasons/129245027?type=crashes
https://rink.hockeyapp.net/manage/apps/152731/app_versions/68/crash_reasons/129253881?type=crashes

josve05a/wikipedia-ios,montehurd/apps-ios-wikipedia,montehurd/apps-ios-wikipedia,wikimedia/apps-ios-wikipedia,wikimedia/wikipedia-ios,anirudh24seven/wikipedia-ios,anirudh24seven/wikipedia-ios,anirudh24seven/wikipedia-ios,wikimedia/apps-ios-wikipedia,wikimedia/wikipedia-ios,julienbodet/wikipedia-ios,wikimedia/apps-ios-wikipedia,wikimedia/wikipedia-ios,montehurd/apps-ios-wikipedia,josve05a/wikipedia-ios,josve05a/wikipedia-ios,julienbodet/wikipedia-ios,josve05a/wikipedia-ios,montehurd/apps-ios-wikipedia,julienbodet/wikipedia-ios,anirudh24seven/wikipedia-ios,josve05a/wikipedia-ios,wikimedia/wikipedia-ios,anirudh24seven/wikipedia-ios,wikimedia/apps-ios-wikipedia,wikimedia/apps-ios-wikipedia,julienbodet/wikipedia-ios,wikimedia/wikipedia-ios,anirudh24seven/wikipedia-ios,montehurd/apps-ios-wikipedia,wikimedia/apps-ios-wikipedia,montehurd/apps-ios-wikipedia,julienbodet/wikipedia-ios,josve05a/wikipedia-ios,wikimedia/wikipedia-ios,josve05a/wikipedia-ios,julienbodet/wikipedia-ios,julienbodet/wikipedia-ios,anirudh24seven/wikipedia-ios,wikimedia/apps-ios-wikipedia,montehurd/apps-ios-wikipedia,julienbodet/wikipedia-ios,anirudh24seven/wikipedia-ios,josve05a/wikipedia-ios,montehurd/apps-ios-wikipedia,wikimedia/wikipedia-ios,wikimedia/apps-ios-wikipedia