[Large screen] Fix searched Subsettings back navigation bug

Settings app registers SubSettings SplitPairRule with clearTop
true, it will finish Settings app if users click back button on
a SubSettings page.

This change registers SubSettings SplitPairRule with clearTop
true when users click a SubSettings item in Settings home menu.

And this change registers SubSettings SplitPairRule with clearTop
false when users click a SubSettings item in search result.

Bug: 204501750
Test: manual
      1. Settings -> Search settings -> search a SubSettings item
         (e.g., Battery)
      2. Click the searched item.
      3. Click back button.
Change-Id: I6e1862de528e971137ae7087de608bbdd79096b2

src/com/android/settings/search/SearchResultTrampoline.java

@@ -25,6 +25,7 @@ import android.os.Bundle;
 
 import com.android.settings.SettingsActivity;
 import com.android.settings.SubSettings;
+import com.android.settings.activityembedding.ActivityEmbeddingRulesController;
 import com.android.settings.overlay.FeatureFactory;
 
 /**
@@ -53,6 +54,11 @@ public class SearchResultTrampoline extends Activity {
         args.putInt(EXTRA_SHOW_FRAGMENT_TAB, tab);
         intent.putExtra(EXTRA_SHOW_FRAGMENT_ARGUMENTS, args);
 
+        // Register SplirPairRule for SubSettings, set clearTop false to prevent unexpected back
+        // navigation behavior.
+        ActivityEmbeddingRulesController.registerSubSettingsPairRuleIfNeeded(this /* context */,
+                false /* clearTop*/);
+
         // Reroute request to SubSetting.
         intent.setClass(this /* context */, SubSettings.class)
                 .addFlags(Intent.FLAG_ACTIVITY_FORWARD_RESULT);