* awair: do not choke on no data
The awair API returns an empty response for various air data queries
when a device is offline. The underlying library (python_awair) does
not directly inform us that a device is offline, since we really can
only infer it from an empty response - there is no online/offline
indicator in the graphql API.
So - we should just ensure that we do not attempt to update device state
from an empty response. This ensures that the platform does not crash
when starting up with offline devices, and also ensures that the
platform is marked unavailable once devices go offline.
* Fix typo
Further proof that coding after 10pm is rolling the dice.
Andrew Hayworth
87a0118082