This property controls whether the list view will display a header, in the form of a foldout that can be expanded or collapsed.
The default values if false.
When this property is set to true, Unity adds a foldout in the hierarchy of the list view and moves
the scroll view inside that newly created foldout. The text of this foldout can be changed with headerTitle
property on the ListView.
If showBoundCollectionSize is set to true, the header will include a TextField to control
the array size, instead of using the field as part of the list.