Waiting list now works for sold-out events

You can now enable the waiting list for an event that is already sold out.

Previously, the waiting list button in the ticketshop was not always shown when the waiting list was activated after the event had already sold out. From now on, the sign-up button appears immediately for sold-out time slots.

Time slots that still have tickets available remain on sale as usual. The separate waiting list setting per time slot also continues to work as before.