Make setAirplaneMode @SystemApi for SetupWizard.

Expose ConnectivityManager#setAirplaneMode and the
NETWORK_SETUP_WIZARD permission so that SetupWizard can call
setAirplaneMode.

Delete setAirplaneMode from the greylist because the permissions
checks on it, since at least 2013, have been for a privileged
permission (CONNECTIVITY_INTERNAL) that normal apps don't have.

Test: m
Bug: 115302596
Change-Id: I28f24d32c4b4b386407e9e0e3514ea9f8854f4a8