Update summary for AllInOneTetherPreference accordingly

The summary for AllInOneTetherPreference in NetworkDashboardFragment is
updated according to tethering state and tether interface chosen by
user.

Bug: 149256198
Test: AllInOneTetherPreferenceControllerTest, TetherEnablerTest,
CodeInspectionTest

Change-Id: I24ba4deabbb02b203e76d32048040d7ccf1b2d22
5 files changed