Make the preference not selectable

"Battery usage data isn't available" should not respond to taps

Bug: 69312966
Test: Manual test
Change-Id: Id450c5a6089a4fb78a5c48a0f460992dc89f49ec

src/com/android/settings/fuelgauge/BatteryAppListPreferenceController.java

@@ -482,6 +482,7 @@ public class BatteryAppListPreferenceController extends AbstractPreferenceContro
             notAvailable = new Preference(mPrefContext);
             notAvailable.setKey(NOT_AVAILABLE);
             notAvailable.setTitle(R.string.power_usage_not_available);
+            notAvailable.setSelectable(false);
             mAppListGroup.addPreference(notAvailable);
         }
     }