Bug 31325: Fix koha-preferences get

To reproduce:
$ perl koha/misc/admin/koha-preferences get MarcFlavour
This will output something like "HASH(0x55dd4d432840)".

To test:
Apply this patch and run the command again:
$ perl koha/misc/admin/koha-preferences get MarcFlavour
This should output something like "MARC21".

Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>

misc/admin/koha-preferences

@@ -238,7 +238,9 @@ my %commands = (
 
         print_usage() unless ( $preference );
 
-        print GetPreference( $preference ) . "\n";
+        my $pref = GetPreference( $preference );
+
+        say $pref->{'value'};
     },
     set => sub {
         my ( $preference, $value ) = @_;