Check portable objset MAC even if local is zeroed

PR #14161 made spa_do_crypt_objset_mac_abd() to ignore MAC errors
if local MAC can not be calculated at the time. But it does not
mean we should also ignore portable MAC errors there.

Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Signed-off-by: Alexander Motin <mav@FreeBSD.org>
Sponsored by: iXsystems, Inc.
Closes #17122