If the mode is PRIVATE_DNS_MODE_PROVIDER_HOSTNAME and hostname is
invalid, we should disable the save button. Otherwise enable the
save button.
Bug: 68030013
Test: RunSettingsRoboTests
Change-Id: If9149c119f1b396a7057590d515b62e7c19b9f99
This option lives in menu. A dialog will show up once this menu
is clicked.
We reuse most of the logic in go/aog/524415 with the following
updates:
1. Use radioGroup instead of directly control radioButton
2. remove bunch of methods if they are only used once.
Following cl will:
1. Remove this feature in development page
2. Add the help link at the bottom of the dialog
3. Disable "Save" button when hostname is invalid.
Bug: 68030013
Test: add for later
Change-Id: I4c6d359dc9c55675858c20e47953ef677b31c3b5