Add a config to force rounded icon for DashboardFragment.

And each page has ability to turn on/off rounded icons. This CL only
adds the flag, it doesn't actually change icon shape yet.

- Boolean config in xml
- New protected method for each DashboardFragment to load config
- Plumb the boolean into DashboardFeatureProvider for future use.
- Remove some unused APIs from DashboardFeatureProvider

Bug: 110405144
Fixes: 79748104
Test: robotests
Change-Id: Id34782e75aa7289967e4dd1f4fe2978688092702

src/com/android/settings/dashboard/SummaryLoader.java

@@ -42,12 +42,6 @@ import com.android.settingslib.utils.ThreadUtils;
 import java.lang.reflect.Field;
 import java.util.List;
 
-/**
- * TODO(b/110405144): Remove this when all top level settings are converted to PreferenceControllers
- *
- * @deprecated
- */
-@Deprecated
 public class SummaryLoader {
     private static final boolean DEBUG = DashboardSummary.DEBUG;
     private static final String TAG = "SummaryLoader";