Fix deletion of waypoints.

`FlightPlan.waypoints` returns a list created from the iterator now, so
removing items from that list does not actually alter the flight plan.

Fixes https://github.com/Khopa/dcs_liberation/issues/489

gen/flights/flightplan.py

@@ -69,8 +69,6 @@ class FlightPlan:
         """A list of all waypoints in the flight plan, in order."""
         return list(self.iter_waypoints())
 
-    
-
     def iter_waypoints(self) -> Iterator[FlightWaypoint]:
         """Iterates over all waypoints in the flight plan, in order."""
         raise NotImplementedError