Fix setVehicleDirtLevel again

[FileEX]

Fix #3233

This PR is an improved version of #3837 - it’s not based on SilentPatch but on the original SA code. Additionally, the PR introduces a new special world property, vehicles_vanilla_dirt, which defaults to false to avoid breaking backward compatibility like in the previous PR (#3894, #3893). The setVehicleDirtLevel function only works if vehicles_vanilla_dirt is set to true.

The PR uses a minimal number of hooks and is based on a clean approach, implementing the GTA function directly (other functions will be reversed later to keep this PR as small as possible).

[qaisjp]

This is not a full code review, but I have a question

Instead of a special world property, why not just enable the patch when someone calls setVehicleDirtLevel for the first time?

Or is the case that this code does more than just make setVehicleDirtLevel work?

[qaisjp]

Is it possible to rewrite this to not use __asm?

GitHub Copilot says this:

// Assuming SetClump takes a single pointer argument and uses cdecl
using SetClumpFn = void(__cdecl*)(void*);

void ForwardSetClump(void* arg)
{
    const auto fn = reinterpret_cast<SetClumpFn>(&CVehicleModelInfoSAInterface::SetClump);
    fn(arg);
}