Remove duplicate result for dark mode

We only keep the one in display settings.

Test: robo test and search dark mode in settings search.
Fix: 155735315
Change-Id: I71041f473944e854ef4601063658021bb9411069

src/com/android/settings/display/darkmode/DarkModeActivationPreferenceController.java

@@ -156,6 +156,6 @@ public class DarkModeActivationPreferenceController extends BasePreferenceContro
 
     @Override
     public int getAvailabilityStatus() {
-        return AVAILABLE;
+        return AVAILABLE_UNSEARCHABLE;
     }
 }