Ensure the intro view is always the top view in the draglayer if it is present

-> On devices post-api-16, we can achieve this just with child drawing order
   but on level 16 devices, child drawing order doesn't give us touch
   dispatch which is problematic for the intro screen.

issue 13796017

Change-Id: Ibf89ae91d8489f2de1eb9c8f235a0e6e6aed1847