OpenID Connect ACR value can't be configured with something else than 'loa-...'

In some parts of our code, the acr value is forced to loa-...:

    my $id_token_acr = "loa-" . $apacheSession->data->{authenticationLevel};

See https://gitlab.ow2.org/lemonldap-ng/lemonldap-ng/-/blob/v2.0/lemonldap-ng-portal/lib/Lemonldap/NG/Portal/Issuer/OpenIDConnect.pm#L1443

As said in code comments:

# TODO: refactor to use _generateIDToken

Because in _generateIDToken we use the configuration settings.