[Provider Model] Internal cleanup - remove Provider Model flag and deprecated legacy UI part.3

Test: atest DefaultSubscriptionControllerTest, NetworkProviderSettingsTest
Bug: 197066557
Change-Id: I7d29b58ca5476ae0bb6fe2e04fecb96164cb1ada

src/com/android/settings/network/telephony/CallsDefaultSubscriptionController.java

@@ -45,10 +45,6 @@ public class CallsDefaultSubscriptionController extends DefaultSubscriptionContr
 
     @Override
     public CharSequence getSummary() {
-        if (Utils.isProviderModelEnabled(mContext)) {
-            return MobileNetworkUtils.getPreferredStatus(isRtlMode(), mContext, mManager, true);
-        } else {
-            return super.getSummary();
-        }
+        return MobileNetworkUtils.getPreferredStatus(isRtlMode(), mContext, mManager, true);
     }
 }