Remove the local cached BluetoothClass

Use BluetoothDevice.getBluetoothClass() to get the cached Bluetooth class
instead of use mBtClass that is local cached.

Bug: 112517004
Test: make -j42 RunSettingsLibRoboTests ROBOTEST_FILTER=CachedBluetoothDeviceTest
Change-Id: I48b974e7ac4e813b498cea0257253f02b4c07dd2
3 files changed