Bug 31247: Fix OPAC authentication when 2FA is enabled

Bug 31247: Fix OPAC authentication when 2FA is enabled

Silly mistake from bug 28786, the $type should be compared to "opac"
instead of "OPAC", erk!

Test plan:
Turn 2FA on
Set it up for an user
Login at the OPAC
=> Without this patch you keep being redirected to the auth form screen
=> With this patch applied you are able to successfully login

Signed-off-by: Caroline Cyr La Rose <caroline.cyr-la-rose@inlibro.com>
Signed-off-by: Victor Grousset/tuxayo <victor@tuxayo.net>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>