Update bluetooth preference to take user to new screen

This CL removes the toggle from the bluetooth preference and instead
takes users to a new dedicated screen for toggling bluetooth status.
On this screen we show a different summary text depending on whether
bluetooth and bluetooth scanning are on/off. Also, we were able to
delegate most of the UI/bluetooth handling to already existing
classes.

Test: robotests
Bug: 77543471
Merged-In: I036a3992bbd78896da8364b55ecc51afc4464b6e
Change-Id: I036a3992bbd78896da8364b55ecc51afc4464b6e