Fix the highlight error after unfolding the device

Unfolding a device generates mutiple lifecycle events and resets the
highlight key.

Check if there's only one activity in the task and then perform the
reset.

Fix: 209016927
Test: manual
Change-Id: I49988fa913270d35a04436777433b7669afb72df

src/com/android/settings/homepage/SettingsHomepageActivity.java

@@ -311,7 +311,7 @@ public class SettingsHomepageActivity extends FragmentActivity implements
     }
 
     private void launchDeepLinkIntentToRight() {
-        if (!ActivityEmbeddingUtils.isEmbeddingActivityEnabled(this)) {
+        if (!mIsEmbeddingActivityEnabled) {
             return;
         }