Three methods for adding hearing aids device into audio switcher.

- Add three methods for subclass to get connected device list
denpending on different profiles.

- Test case for these methods.

Bug: 78142719
Test: make RunSettingsRoboTests ROBOTEST_FILTER="AudioOutputSwitchPreferenceControllerTest" -j28
Change-Id: Ia1367a53ab6a3432878a514490722871ed878954