hide the "Storage manager" toggle from Storage screen

"Storage manager" is supposed to automatically remove backed up photos and videos.
This functionality is not implemented in AOSP, i.e. this toggle doesn't actually work.

res/values/config.xml

@@ -564,7 +564,7 @@
     <string name="config_documents_and_other_storage_category_uri" translatable="false">content://com.android.providers.media.documents/root/documents_root</string>
 
     <!-- Whether to show Smart Storage toggle -->
-    <bool name="config_show_smart_storage_toggle">true</bool>
+    <bool name="config_show_smart_storage_toggle">false</bool>
 
     <!-- Whether to support large screen -->
     <bool name="config_supported_large_screen">false</bool>