During private key loading, there is no indication if the provided 'aux data' is corrupted

[MarkLuk]

Either the library should provide means to check aux data integrity before passing it to hss_load_private_key or hss_load_private_key shall return an indication that aux data is corrupted.

Something like https://github.com/cisco/hash-sigs/blob/73310fdf7f83013adba5b393264955b9ca5f54cf/hss_generate.c#L400

Check if expanded_aux is 0 and return a warning to the user via info->error_code