ML#124 - Ensure Expired Links Fail Gracefully

[kodinkat]

• fixes: #124

[corsacca]

@kodinkat this will make sure all links are expired if the expired value isn't set?

[corsacca]

@kodinkat returning expires tomorrow seems like it could cause missinformation

Instead, in the places where determine_links_expiry_point is called, like in has_links_expired and fetch_links_expired_formatted_date, can we return from there if expiry not set?

[corsacca]

THanks @kodinkat !