Allow new users to configure WiFi details

- Remove the limitation of the Settings UI for Admin user only.

- See b/206986392#comment32 for a screenshot.

Bug: 206986392
Test: manual test
make RunSettingsRoboTests ROBOTEST_FILTER=WifiNetworkDetailsFragmentTest

Change-Id: I31971d644cd475123255ffb6c93c16ff171f77ad