Define a constant Sliceable#NO_RES for no resource cases

Fix: 204733076
Test: build
Change-Id: Ifa3b9db0e915a3ec056ad68a9a1862811594d423

src/com/android/settings/flashlight/FlashlightSlice.java

@@ -120,7 +120,7 @@ public class FlashlightSlice implements CustomSliceable {
     @Override
     public int getSliceHighlightMenuRes() {
         // no landing page in Settings
-        return 0;
+        return NO_RES;
     }
 
     private static String getCameraId(Context context) throws CameraAccessException {