udisks2: Change display name for crypto_unknown devices

The udisks id_type crypto_unknown is used for devices which are possibly
encrypted.

In udisks, this uncertainty is conveyed to the user by using the long name
"Possibly encrypted", and the short name "Encrypted?".

GVfs used to display all devices with id_usage == "crypto" as
"Encrypted". This commit instead uses the string "Possibly Encrypted" if
id_type == "crypto_unknown".
3 jobs for consistent-string-for-crypto-unknown in 2 minutes and 30 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Test
passed #367524
fedora

00:02:30

manual #367525
allowed to fail manual
gnome-build-meta-manual
manual #367526
allowed to fail manual
update-image