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

tests/robotests/src/com/android/settings/accounts/AccountDetailDashboardFragmentTest.java

@@ -130,7 +130,7 @@ public class AccountDetailDashboardFragmentTest {
 
         final FragmentActivity activity = Robolectric.setupActivity(FragmentActivity.class);
         final Preference preference = new Preference(mContext);
-        dashboardFeatureProvider.bindPreferenceToTile(activity,
+        dashboardFeatureProvider.bindPreferenceToTile(activity, false /* forceRoundedIcon */,
                 MetricsProto.MetricsEvent.DASHBOARD_SUMMARY, preference, tile, null /* key */,
                 Preference.DEFAULT_ORDER);