Inform user about unset card key or card key without certificate
Show "no key" in Certificate column if card key is unset and show
"no associated certificate" if there is no certificate for this card key.
Both texts are displayed in italics.
(cherry picked from commit 816db9510d38adc0ad3e3a0ce143a74ea78f134d)
- GnuPG-bug-id: T7018