BUG: Fix "orphan view" issue in layout manager
Created by: jcfr
**** WORK IN PROGRESS **** Todo:
- Update test. Test doesn't pass yet. It needs to consider the "MappedInLayout" attribute when checking visibility
- Update documentation to clearly document MappedInLayout vs Visibility. **** WORK IN PROGRESS ****
The node visibility is now set considering both the "MappedInLayout" and the Visibility properties.
It fixes a regression re-introduced in r24209 (ENH: Update layout view factory to consider view node visibility property) that was originally fixed in r24175 (BUG: Fixed orphaned views displayed in secondary layout widgets).