Add "delete mode" option on mode configuration page

Flag: android.app.modes_ui
Bug: 346575126
Test: manual
Change-Id: I0d085eb54ef5fa07f312bdddf0219855bf1c2ef4

src/com/android/settings/notification/modes/ZenModeFragmentBase.java

@@ -20,6 +20,7 @@ import android.app.AutomaticZenRule;
 import android.content.Context;
 import android.os.Bundle;
 import android.util.Log;
+import android.view.MenuItem;
 import android.widget.Toast;
 
 import androidx.annotation.NonNull;
@@ -108,6 +109,18 @@ abstract class ZenModeFragmentBase extends ZenModesFragmentBase {
         updateControllers();
     }
 
+    @Override
+    public final boolean onOptionsItemSelected(MenuItem item) {
+        if (mZenMode != null) {
+            return onOptionsItemSelected(item, mZenMode);
+        }
+        return super.onOptionsItemSelected(item);
+    }
+
+    protected boolean onOptionsItemSelected(MenuItem item, @NonNull ZenMode zenMode) {
+        return true;
+    }
+
     private void updateControllers() {
         if (getPreferenceControllers() == null || mZenMode == null) {
             return;