Use default network template in billing cycle settings.

- if the network template is not set in the bundle arguments, use the
default network template for getting the billing data.
- change to use ConnectivityManager.from(context) in DataUsageUtils to
be consistent with the usage in other methods.

Change-Id: I25eb27f8f26d9ecafc66aa2c69806e94c6b63499
Fixes: 117452991
Test: make RunSettingsRoboTests
4 files changed