Redundant choose vehicle prompt

[zaimoni]

We already had a check that there was a vehicle nearby before attempting to refill it at a gas station. If there is only one vehicle, just default to that.

Landed in 7ba24e4 .

We could go further and pre-screen by whether the vehicle is refillable, but that is a more invasive UI change. (NPC handling of vehicles, would want something like this.)