Dark theme drop down does not show selected option

a place holder for the summary was updated in commit https://googleplex-android-review.git.corp.google.com/changes/platform%2Fpackages%2Fapps%2FSettings~9818614/revisions/3/files/res%2Fxml%2Fdark_mode_settings.xml/download?parent=1
This change is reverted in this CL

Test: manual
Fixes: 145672617
Change-Id: I41443e7334487e3afac0343333a9ed289d2fe390
diff --git a/res/xml/dark_mode_settings.xml b/res/xml/dark_mode_settings.xml
index c3985e6..9247a0c 100644
--- a/res/xml/dark_mode_settings.xml
+++ b/res/xml/dark_mode_settings.xml
@@ -24,7 +24,7 @@
     <DropDownPreference
         android:key="dark_ui_auto_mode"
         android:title="@string/dark_ui_auto_mode_title"
-        android:summary="@string/summary_placeholder"
+        android:summary="%s"
         android:entries="@array/dark_ui_scheduler_preference_titles"
         android:entryValues="@array/dark_ui_scheduler_preference_titles"
         settings:controller="com.android.settings.display.darkmode.DarkModeScheduleSelectorController"