[Hide DCK Device] Move the aconfig flag for hide DCK device feature to settingslib

Test: atest: com.android.settings.bluetooth.ConnectedBluetoothDeviceUpdaterTest
Test: atest: com.android.settings.bluetooth.SavedBluetoothDeviceUpdaterTest
Bug: 323298503
Bug: 324475542
Flag: ACONFIG com.android.settingslib.flags.enable_hide_exclusively_managed_bluetooth_device DEVELOPMENT
Change-Id: I558b749501807afcea7c15d94f498f01162a6f1e