Independent methods to enable/disable BLE mode

* Use IBluetoothManager.enableBle() and disableBle() to toggle BLE only
  mode instead of updateBleAppCount() then enable().
* Fix BluetoothAdapter.disableBle sometime won't disable Bluetooth.
* Add active log if Bluetooth is disabled via disableBle().

Bug: 139454316
Test: enableBle() -> disableBle() and check Bluetooth is OFF.
Change-Id: I173d5fed1b47ff68a6504741e25754e65cbd1455