Hides the specified layout item.
A BaseLayoutItem descendant which represents the layout item to hide.
End-users can hide and show layout items by moving them to or from the Customization Form via drag and drop. To show a hidden item use the BaseLayoutItem.RestoreFromCustomization method.
When layout items are hidden to the Customization Form, they do not retain their positions in the layout. To preserve the position, use Visibility instead.