bugfix: Chinooks and Helixes now correctly wait for their passengers to disembark

[Stubbjax]

Fixes #703 from the patch repository

This change adjusts Chinook and Helix behaviour so that they evacuate their passengers with the correct timing. In the retail game, the ExitDelay field of the TransportContain module is ignored and all passengers are immediately evacuated - unless the aircraft is already landed (e.g. repairing at an airfield or waiting for passengers to board). With this change, the ExitDelay field is always respected and remains consistent across all evacuation pathways. If the immediate evacuation behaviour from the retail game is preferred, the ExitDelay can be simply tweaked to 0.

As a bonus, the double evacuation bug is also fixed as a result of this change.

Before

The Chinook dumps all passengers in a single frame

IMPROPER_EVAC.mp4

The Chinook lands twice if given two or more evacuation orders before all passengers have disembarked

DOUBLE_EVAC.mp4

After

The Chinook correctly unloads a passenger every 100ms as defined by the ExitDelay in the TransportContain module

PROPER_EVAC.mp4