Predefined scope ValidatorFactory: uninitialized bean class shouldn't throw an exception

I have been a bit too pedantic here: if the bean class is unknown from the predefined scope VF, we have to consider it doesn't have any constraint.

Obviously, unconstrained beans won't be registered by Quarkus and thus validating them will lead to an exception. It can happen more often than not when validating REST services method parameters for instance.