even if the options *could* be set in the frontend, the backend
actually has to do validation of those settings, thus we should not
make that a browser setting
additionally, having the value 'preferred' does not actually make sense,
since it does not add any security (the backend skips the
userverification check then)
This reverts commit aca4c2b5a9.
Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>
b452e2df74