The flight plan should surface unexpected statuses

[eggrobin]

The default

Principia/ksp_plugin_adapter/flight_planner.cs

Lines 418 to 419 in 3957b99

	string remedy_message = "changing the flight plan"; // Preceded by "Try".
	string status_message = "computation failed"; // Preceded by "The".

gets shown when the status is not one of ABORTED, FAILED_PRECONDITION, INVALID_ARGUMENT, or OUT_OF_RANGE.

This is not a useful message, and silently absorbing the unexpected message prevents us from diagnosing potential issues.

Encountered by Falcon on discord:

[eggrobin]

I suspect the status here is DEADLINE_EXCEEDED (the ephemeris does not go all the way to the requested 8000 days).

I am not sure whether the current behaviour is such that we eventually compute the requested ephemeris, pushing it forward a little at each frame, or whether we ignore the issue until a modified flight plan is requested (the former would be the expected behaviour, and it is the behaviour for predictions; the error message should accordingly ask the user to wait for the prolongation of the ephemeris).