Fixed a bug where the dozemode wasn't working correctly

There where 2 different issues which could lead to the dozemode
not working correctly:
1. The new workarabout where we show the expanded notification
if it has the same size as the collapsed, requires that dozemode
is also called on the right notification
2. When the children were not layed out yet, this calculation could be
wrong and the wrong child was selected, leading to the same issue.

Bug: 26459664
Change-Id: Ib67dcaf2ba9b8b9a1bfa5ece5b7d6c4dff677939