SystemUI: Fix data tile doesn't change with default data card issue

By current design, the data tile can control all cards data, and it
refresh its state according to the first card.
Dds tile also refresh its state according to the first card.
When data on/off, the changed URI is Settings.Global.MOBILE_DATA + 0/1,
but not Settings.Global.MOBILE_DATA.

The data tile should just control the default data card and refresh
according to it.
Change the URI to watch for data changes and dds switch.

CRs-Fixed: 755171

Change-Id: I73ab6b40f4ef28fccb3046b6dbc63b754356ea91