AdapterState: Simplify state transitions

- Split PendingCommandState into
  - TurningOnState
  - TurningOffState
  - TurningBleOnState
  - TurningBleOffState
- Move timeouts to enter() and exit()
- Move the native callback to AdapterService
- Remove scan setting disable

Bug: 72435402
Fixes: 66452171
Fixes: 66711270
Test: runtest bluetooth
      Toggle bluetooth from settings rapidly
      act.py -tc BtStressTest:test_toggle_bluetooth
Change-Id: Ic9728a9717dac7b337978deeb58104b38fea641e