SystemUI: various fixes to data type display

- Hide data type when Wi-Fi is in use (CAF bug)
- Display "!" when data is disabled (CAF bug)
- Display type in QS when Wi-Fi is connected to captive portal (AOSP bug)

CAF bug was introduced in 228bccb9

The proper logic is described at https://android.googlesource.com/platform/frameworks/base/+/23dd176

Change-Id: I7a34077d604c66c357809c634fe64c570a16e260