luks2: need to check the availability of a JSON area

[Vitalii Hordii <vitalnodo@xxxxxxxxxxx>]

Hello,

I had some problems with restoring a luks2 partition after using, for 
example, mkfs.ntfs because it only leaves a 2nd JSON area without a 
secondary binary header, which I had to create myself. What if there was 
a function in libblkid that allows one to determine if there is a 2nd 
JSON and if there is a chance of recovery? Because as I see here, 
automatically repairing 
https://gitlab.com/cryptsetup/cryptsetup/-/issues/750 is apparently 
missing due to the lack of checking if there is an area here in 
libblkid. Also this seems to be a pretty popular problem on the internet 
when it comes to installing other operating systems. Would it be okay to 
add such a feature?

Best regards, Vitalii