Move "Build Number" slice to a different controller.

There are 2 build number tiles in settings: Android version -> Build
number and About phone -> build number.

The way we index breadcrumb for each slice is making some client
confused. So this change moves the slice capability from Androi
version>BuildNumber to About phone.

Fixes: 130652710
Test: reindex, robotest
Change-Id: I9054d0db124b706e7984cd3d19774bb604bd7fd3