sensors: move mag aggregation to new VehicleMagnetometer WorkItem

- purge all reminaing magnetometer IOCTL usage
 - mag calibration add off diagonal (soft iron) scale factors

src/modules/sensors/data_validator/tests/tests_common.cpp

@@ -100,4 +100,4 @@ void fill_validator_with_samples(DataValidator *validator,
 	*timestamp_io = timestamp;
 	*value_io = val;
 
-}
+}