[QoL] Ambulance medic pair driving

[SwiftShader]

Pair driving in an ambulance vehicle should distribute the income from healing damaged players to each medic class player in the vehicle. This should make the gameplay closer to real-life situations and resolves the issue when two or more medics arrive at the scene (of a robbery).

[Scorpyo]

This is now done as per https://saesrpg.uk/topic/33845/introducing-saes-1-6-part-2?