Fix bundle key in IndividualPickerFragment

Bug: 132784008
Change-Id: I924d253d3340f100fc3f6599d0e2124aa8ae38c0
diff --git a/src/com/android/wallpaper/picker/individual/IndividualPickerFragment.java b/src/com/android/wallpaper/picker/individual/IndividualPickerFragment.java
index 8234477..654ec13 100755
--- a/src/com/android/wallpaper/picker/individual/IndividualPickerFragment.java
+++ b/src/com/android/wallpaper/picker/individual/IndividualPickerFragment.java
@@ -327,7 +327,7 @@
     @Override
     public void onSaveInstanceState(@NonNull Bundle outState) {
         super.onSaveInstanceState(outState);
-        outState.putInt("NIGHT_MODE",
+        outState.putInt(KEY_NIGHT_MODE,
                 getResources().getConfiguration().uiMode & Configuration.UI_MODE_NIGHT_MASK);
     }