Remove DynamicAvailabilityPreferenceController.

- This class is over complex to use, and get in the way of show/hide
  pref when availability change.
- The function from DynamicAvailabilityPreferenceController can be done
  with PreferenceCategoryController.

Bug: 68956750
Bug: 32953042
Test: robotests
Change-Id: Ia7b7e214c072b8c77f5de3d959fdb1dc79217f76