This works as of android 7.1.1, non-rooted
adb shell am start -a android.intent.action.MAIN -n com.android.settings/.wifi.WifiSettings && adb shell input keyevent 23 && adb shell input keyevent 23
This will launch the activity and then send the DPAD center keyevent. I added another DPAD center as an experiment to see if you can enable it in the same way.