ChannelLazyLoadingChangedBySet keeps reference to HstNode which is never allowed for enhanced hst model object

The enhanced hst model is never allowed to maintain references to any HstNode. This is because the hst model is append only (but mostly immutable). However, HstNode's are part of a different model (detached jcr model) with its own lifecycle and / or reload cycle. They are not allowed to be used from enhanced hst model config objects (HstNode can be reloaded while a request uses a model instance)