SAE: Do not allow password identifier to be used without H2E

SAE: Do not allow password identifier to be used without H2E

When the concept of SAE password identifiers was introduced in IEEE
P802.11REVme/D1.0, there was no requirement to use H2E with them.
However, this was changed for the published IEEE Std 802.11-2020 to
require H2E to avoid certain cases where the password identifier could
not have been parsed robustly.

Commit e36a5894d0c0 ("SAE: Use H2E whenever Password Identifier is
used") started forcing H2E to be used when password identifiers were in
use with SAE. However, it did not enforce rejection of cases where H2E
was not enabled by a non-compliant implementation. Add that explicit
check during parsing of SAE commit messages.

Signed-off-by: Jouni Malinen <quic_jouni@quicinc.com>