Add DND Settings suggestion

Cherry-picked from pi-dev ag/4019736

Test: SettingsSuggestionsTest, ZenOnboardingActivityTest
Change-Id: Ie78c9cf8287ee56bc4596efe20d27f8eb432ab6c
Bug: 78445134

tests/robotests/src/com/android/settings/support/NewDeviceIntroSuggestionActivityTest.java

@@ -78,7 +78,7 @@ public class NewDeviceIntroSuggestionActivityTest {
         final long currentTime = System.currentTimeMillis();
 
         getSharedPreferences().edit().putLong(PREF_KEY_SUGGGESTION_FIRST_DISPLAY_TIME,
-                currentTime - 2 * PERMANENT_DISMISS_THRESHOLD);
+                currentTime - 2 * PERMANENT_DISMISS_THRESHOLD).commit();
         assertThat(isSuggestionComplete(mContext)).isTrue();
     }