Update Notification preferences UI in new IA.

- Refactored ConfigureNotificationSettings to be more modular
- And tests

Bug: 31799948
Test: RunSettingsRoboTests
Change-Id: I2ecd8930a6aa501c1e625cab6ed25a46f3437e85

tests/robotests/src/com/android/settings/dashboard/DashboardFragmentTest.java

@@ -154,7 +154,7 @@ public class DashboardFragmentTest {
         mTestFragment.bindPreferenceToTile(mContext, preference, tile, "123");
 
         assertThat(preference.getFragment()).isNull();
-        assertThat(preference.getIntent()).isNotNull();
+        assertThat(preference.getOnPreferenceClickListener()).isNotNull();
         assertThat(preference.getOrder()).isEqualTo(-tile.priority);
     }