Show certificate list and Learn Certificates button if it makes sense
Show list of card certificates if any certificates are known for the card
keys.
Show Learn Certificates button if any certificate of a card key is unknown.
The text "There are unknown certificates on this card." is only shown
if no certificates for the card keys are known.
(cherry picked from commit a985b6502c15ff072441b9782b044034f6c8e0d6)
- GnuPG-bug-id: T6830