[Settings] Apply proxy design to data usage

Enable proxy to subscription manager in data usage UI.

Bug: 141833767
Test: manual
make RunSettingsRoboTests -j ROBOTEST_FILTER=BillingCyclePreferenceTest
make RunSettingsRoboTests -j ROBOTEST_FILTER=CellDataPreferenceTest
make RunSettingsRoboTests -j ROBOTEST_FILTER=DataUsageListTest
make RunSettingsRoboTests -j ROBOTEST_FILTER=DataUsageSummaryTest
make RunSettingsRoboTests -j ROBOTEST_FILTER=DataUsageUtilsTest
make RunSettingsRoboTests -j ROBOTEST_FILTER=MobileDataEnabledListenerTest

Change-Id: Id119738dc16ece8767c088b9a0794997e4b0334f