Implement SatelliteModeListener in kt + FLAG

* Set up feature behind a flag
* No longer require a specific class to hold it
* fix async issue by creating the observer with the bms looper
* fix init slow down by registering and reading settings on the bms
  thread
* add test to check all expected behaviors

Bug: 286260653
Bug: 262605980
Bug: 289584302
Bug: 286602847
Test: m service-bluetooth
Test: atest ServiceBluetoothRoboTests
Change-Id: Ic1741d77094d41e8718bc773a2266ee1e8998fa1