JBIDE-17675 Validation error for subclasses of DeltaSpike JsfModuleConfig class

Validation of specializing bean is fixed. Check for a public constructor
with no parameters in superclass is replaced with a check that superclass
is a managed bean.
Do we really need to check constructors here?
Is it enough to make sure the supperclass is a bean? The supperclass bean may be initialized programmatically or via some extension.