Set correct network type when launching wifi usage data.

- when launching wifi data usage, need to explicitly set the network
type to wifi. Otherwise, the data usage list will try to show data for
the default mobile data usage.

Change-Id: I819538d2c53664635bc1c2a721d6d7f6799c6123
Fixes: 123205630
Test: make RunSettingsRoboTests
2 files changed