* When the preference is changed by the user, it will update the UI
* When the Developer options is enabled, it will set the system property
to default number
* Change string "Maximum number of connected Bluetooth audio devices" to
"Maximum connected Bluetooth audio devices" per discussion with Lindsay
Bug: 71603731
Test: m
ROBOTEST_FILTER="BluetoothMaxConnectedAudioDevicesPreferenceControllerTest"
RunSettingsRoboTests -j40
Change-Id: I3e59534585065c84530da73ffded21894c845ce9
The new developer option modifies the system property
"persist.bluetooth.maxconnectedaudiodevices"; it allows testing
multiple connected devices for A2DP, AVRCP, HFP.
Bug: 71603731
Test: Robolectric test
Change-Id: Ie7887065f98193f4f34e0ff4a29959694e417124
