Also: fix a bug where the actual current mode is not read correctly
from settings on initialization.
Test: as follows
- built, flashed, booted
- manual test behaves as expected
- make -j50 RunSettingsRoboTests ROBOTEST_FILTER=PrivateDnsModeDialogPreferenceTest passes
- make -j50 RunSettingsRoboTests ROBOTEST_FILTER=PrivateDnsPreferenceControllerTest passes
Bug: 34953048
Bug: 64133961
Change-Id: I0b845b3894a47b837abf5de273d1ada642ef5a23
Bug: 64133961
Fixes: 74844869
Test: visual test and interaction
also updated tests and checked they pass
Change-Id: I7c8d50e5941c2a7dd46014932bdace14dc222c80