[Pair hearing devices] Add "Hearing devices" to show connected hearing devices

Bug: 237625815
Test: make RunSettingsRoboTests ROBOTEST_FILTER=AvailableHearingDeviceUpdaterTest
Change-Id: I15bff230cac29fdbad13d452878bc57b57d9773e

src/com/android/settings/accessibility/AccessibilityHearingAidsFragment.java

@@ -48,6 +48,7 @@ public class AccessibilityHearingAidsFragment extends AccessibilityShortcutPrefe
     @Override
     public void onAttach(Context context) {
         super.onAttach(context);
+        use(AvailableHearingDevicePreferenceController.class).init(this);
         use(SavedHearingDevicePreferenceController.class).init(this);
     }