vehicle_global_position: remove velocity fields (duplicates of local vx, vy, vz)

* attitude_estimator_q: get velocity from local position (if available)

src/modules/mavlink/mavlink_messages.cpp

@@ -2067,7 +2067,7 @@ public:
 private:
 	MavlinkOrbSubscription *_local_pos_sub;
 	uint64_t _local_pos_time = 0;
-	vehicle_local_position_s _local_position   = {};
+	vehicle_local_position_s _local_position = {};
 
 	MavlinkOrbSubscription *_global_pos_sub;
 	uint64_t _global_pos_time = 0;