Change ScrollView to NestedScrollView for screen size page

To make sure the collapsing toolbar work as usual, we need to use
NestedScrollView instead of ScrollView in the screen size page.

Bug: 176896338
Test: manual test and visual verified
1) Navigate to Settings -> Display -> Display size
2) Change the size on the seekbar
3) Observe and check if the preview window can be scrolled

Change-Id: Ia5bb66ef63b9d9a7713cebddbf6ab6258ff82b8d