Show ticket details when check-in already completed

[cbellone]

Discussed in #1479

^{Originally posted by domfitty August 16, 2025}
In case of a ticket with check-in already completed, it would be useful to display the ticket details on the Android app instead of only showing the error message.
This way, the venue staff can:

• verify that the check-in has already been done
• see the ticket category to guide the guest to the correct section