* web: fix 6742: empty web certificate request needs to return null, not undefined This replaces the `undefined` setting of the certificate search wrapper to `null` when the admin requests no certificate. * only set singleton if we don't have an instance Signed-off-by: Jens Langhammer <jens@goauthentik.io> --------- Signed-off-by: Jens Langhammer <jens@goauthentik.io> Co-authored-by: Jens Langhammer <jens@goauthentik.io>