Expandable Area does not respect scrollbox boundaries unless set to fill

There is an issue where Expandable Area does not respect scrollbox boundaries unless set to fill. This occurs when the scrollbox is a child of another component. This issue does not appear to be a regression.

Versions Tested: Issue occurs on all versions tested
4.17.2 - CL: 3658906
4.18.2 - CL: 3794801
4.19.0 - CL: 3776583

1. Create a new project (no template or starter content needed)
2. Create a new widget blueprint > name it "TestBP" > Open TestBP
3. Add a vertical box
4. Add a scroll box as a child of the vertical box
5. Add an expandable area as a child of the scroll box
6. In the hierarchy expand the options for the expandable area and add a text block as a child of the expandable area's body
7. In the details panel for the text block > Add A lot of text to trigger the scroll box when it is expanded
8. In the level blueprint > create the widget > add to the viewport > and set the mouse cursor to show
9. PIE
   Result: When the Expandable area is expanded it ignores the scroll box unless the scroll box is set to the fill setting
   Expected Result: Expandable area follows the scroll box