Add LE Audio allow list feature switcher in the developer option menu

Add a switcher to enable/disable LE audio allow list feature. The switcher
could be enabled by setprop ro.bluetooth.leaudio_allow_list.supported=true

Bug: 239768625
Test: make RunSettingsRoboTests ROBOTEST_FILTER=BluetoothLeAudioAllowListPreferenceControllerTest
Change-Id: I290da870d952abd20bc25db7924fcc53ac39f880
5 files changed