Update dark mode in accessiblity settings

There was an entry point to dark mode that wasn't updated when the
display settings one was changed to point to a new screen. This
change makes it so that clicking dark mode in accessiblity also
opens the same screen.

Test: robotests pass
Bug: 129406772
Change-Id: I0ad830638e04e5520cdf7de6927764fa6b68a179

tests/robotests/src/com/android/settings/accessibility/AccessibilitySettingsTest.java

@@ -156,7 +156,7 @@ public class AccessibilitySettingsTest {
 
     @Test
     public void testDarkUIModePreferenceSummary_shouldUpdateSummary() {
-        final ListPreference darkUIModePreference = new ListPreference(mContext);
+        final Preference darkUIModePreference = new Preference(mContext);
         final DarkUIPreferenceController mController;
         doReturn(darkUIModePreference).when(mSettings).findPreference(
             DARK_UI_MODE_PREFERENCE);