Show empty detail screen (on tablet) on nothing loaded

TESTED:
- People on Phone should work as we expect.
  (this change shouldn't affect Phone experience at all)
- People on Tablet, landscape and portrait
-- nothing should be shown when no contact is selected
   on boot
-- detail should be shown when a contact is selected
-- nothing should be shown when filter has changed and
   no contact is selected
-- detail should be shown when filter has changed and
   a contact is selected after that
-- orientation change should not cause any problem

Bug: 5084998
Change-Id: Ieed0b551655b7ee3b3872117eca50af90df30021