Resolve a form contribution's empty behaviour / count flag: its own
registration value wins, then the parent entity default, then the built-in default.
A value that is not one of the allowed ones counts as unset. The relationship
readers above pass the relationship's own value through these.
Resolve a form contribution's empty behaviour / count flag: its own registration value wins, then the parent entity default, then the built-in default. A value that is not one of the allowed ones counts as unset. The relationship readers above pass the relationship's own value through these.