Set elevation when the first item is not completely visible

* This CL fixes a bug where elevation is not seen in group view when the
  first item is not completely visible.
* The bug is only seen in group view and not in account view, because
  there is a "search_header" in account view. The "search_header" is an
  item in list view but is not a visible contact. So the first contact
  in account view is actually the second item in the list view.

Bug 30358448

Change-Id: I04b9d7f54a154f8aea9515f376886abe13781df0