Add dark theme custom type into the dark theme settings page

Also fix some test cases.

I'd prefer using Robolectric shadows rather than mocking Android
framework classes. However, I can't do that in this CL due to the
lack of multiple shadow classes support.

Test: make RunSettingsRoboTests -j56
      ROBOTEST_FILTER=com.android.settings.display.darkmode.*
Bug: 215182463
Change-Id: If557d2933927a5dd0fadd3f6db6bb6f0ab7dd5ee

src/com/android/settings/display/darkmode/DarkModeCustomPreferenceController.java

@@ -15,21 +15,20 @@
 
 package com.android.settings.display.darkmode;
 
-import android.app.Dialog;
+import static android.app.UiModeManager.MODE_NIGHT_CUSTOM;
+
 import android.app.TimePickerDialog;
 import android.app.UiModeManager;
 import android.content.Context;
 import android.text.TextUtils;
+
 import androidx.preference.Preference;
-import androidx.preference.PreferenceScreen;
+
 import com.android.settings.core.BasePreferenceController;
-import com.android.settings.dashboard.DashboardFragment;
 
 import java.time.LocalTime;
 import java.time.format.DateTimeFormatter;
 
-import static android.app.UiModeManager.MODE_NIGHT_CUSTOM;
-
 /**
  * Controller for custom mode night mode time settings
  */
@@ -89,7 +88,9 @@ public class DarkModeCustomPreferenceController extends BasePreferenceController
 
     @Override
     protected void refreshSummary(Preference preference) {
-        if (mUiModeManager.getNightMode() != MODE_NIGHT_CUSTOM) {
+        if (mUiModeManager.getNightMode() != MODE_NIGHT_CUSTOM
+                || mUiModeManager.getNightModeCustomType()
+                        != UiModeManager.MODE_NIGHT_CUSTOM_TYPE_SCHEDULE) {
             preference.setVisible(false);
             return;
         }