Misc code cleanup in InputDeviceSensorManager

Clean up code in sensor manager by removing dead code,
ensuring proper synchronization, and some small style changes.

Notable changes:
- Sensor methods in InputManager are not being used, as
  InputDeviceSensorManager is the entry pointer for those APIs, and it
  uses InputManagerGlobal directly. So remove unnecessary sensor methods
  in InputManager.

Bug: 290254916
Test: atest InputDeviceSensorManagerTest
Change-Id: I41b8ee6e0067374950ad45dc66699be6fbabfc65