Add Data usage slice in Contextual Settings Homepage

- Add Data usage card that implements CustomSliceable in Contextual Settings
Homepage.
- Add test case for Data usage slice.

Bug: 114796538
Test: robotests, manual, SliceViewer
Change-Id: I66a046e8f589a477007ea73e1b22420d3efdebde

src/com/android/settings/slices/CustomSliceManager.java

@@ -20,6 +20,7 @@ import android.content.Context;
 import android.net.Uri;
 import android.util.ArrayMap;
 
+import com.android.settings.homepage.deviceinfo.DataUsageSlice;
 import com.android.settings.wifi.WifiSlice;
 
 import java.util.Map;
@@ -87,5 +88,6 @@ public class CustomSliceManager {
 
     private void addSlices() {
         mUriMap.put(WifiSlice.WIFI_URI, WifiSlice.class);
+        mUriMap.put(DataUsageSlice.DATA_USAGE_CARD_URI, DataUsageSlice.class);
     }
 }