Clean up remaining Flight.from_cp users.

The preferred API for this has been `Flight.departure` for a while.

qt_ui/models.py

@@ -145,7 +145,7 @@ class PackageModel(QAbstractListModel):
         delay = datetime.timedelta(
             seconds=int(flight.flight_plan.startup_time().total_seconds())
         )
-        origin = flight.from_cp.name
+        origin = flight.departure.name
         return f"{flight} from {origin} in {delay}"
 
     @staticmethod