Fix NFC state switched off every time user entered connection preferences page

NfcAirplaneModeObserver added a scenario that
switched NFC off every time  a user entered connection
preferences page if airplane mode was on.
Even when a user manually switched on NFC, the observer would still
turn NFC off when re-entering connection preferences page.

GSAM TS.27 certification requires NFC state to be consistent
under AirplaneMode before and after reboot the device.
NfcAirplaneModeObserver breaks the requirement
because it would always switch NFC off under airplane mode
when a user checked the NFC state in settings page.

Fix it by removing NfcAirplaneModeObserver.
Keep the NFC state consistent.


Bug:128384879
Test: make RunSettingsRoboTests / Check Nfc on/off Status
Merged-In: If4c8e47c2509b09e8bc1a464e1ab329b945e3d20
Change-Id: If4c8e47c2509b09e8bc1a464e1ab329b945e3d20