SystemUI: fix NFC tile sometimes hiding

- Check whether NFC is supported based on device features

- Don't hold a reference to the NFC adapter - query it when we need it
  (not using getDefault, but the internal method, if we use the default,
  querying for the adapter before the service was spun up would lead to
  systemui never having a valid refernce to an adpater).

Ticket: CYNGNOS-1943, CYNGNOS-2866
Change-Id: Iba8b668406ca96183aafcf9a55d60c6d89d70061
Signed-off-by: Roman Birg <roman@cyngn.com>
(cherry picked from commit 2c755a67)