Update LocalBluetoothProfile api

This CL include following change:

1. Rename isPreferred() to isEnabled().
2. Rename getPreferred() to getConnectionPolicy().
3. Rename setPreferred() to setEnabled().
4. Remove connect()/disconnect() since when call setEnabled() BT
   stack will base on input state to do connect/disconnect
   automatically.
5. Add/update test case.

Bug: 141582844
Test: make -j42 RunSettingsLibRoboTests
Change-Id: I9aa7d5157028671fcda705bf5cb957c26c4204ad
Merged-In: I9aa7d5157028671fcda705bf5cb957c26c4204ad