Fix BottomNavigationView label placement.

Use the baseline of the labels for positioning them. Previously
it was 8dp from the bottom of the view, now it is 10dp from the baseline
of the text. This makes it follow the spec for this widget.

Bug: 33794750
Test: no test, visual change
Change-Id: Iaf6534937ee5d66651c1e04d805fd7bcab3ea44c
2 files changed