Update dragged elevation to use shared value (at 3dp)

- Had to bump elevation of drop target so need to bumpe elevation
  of dragged views

Flag: com.android.wm.shell.enable_bubble_anything
Test: manual / visual - drag a bubble or drag expanded view and observe
                        the drop targets
Bug: 403276099
Change-Id: I15a1deb055c590b1f46261fcc307120fcb685c08