cert_find: fix call with --all
    
    When ipa cert-find --all is called, the function prints the
    certificate public bytes. The code recently switched to OpenSSL.crypto
    and the objects OpenSSL.crypto.X509 do not have the method
    public_bytes(). Use to_cryptography() to transform into a
    cryptography.x509.Certificate before calling public_bytes().
    
    Related: https://pagure.io/freeipa/issue/9331
    
    Signed-off-by: Florence Blanc-Renaud <flo@redhat.com>
    Reviewed-By: Rob Crittenden <rcritten@redhat.com>