bugfix(module): Consistently yield experience for direct flame kills

[Stubbjax]

This change causes units and buildings that die via flammable status to consistently yield experience to the flammable status source.

In 1.04, the flammable update damage tick can score the kill on a unit or building and negate any experience that should otherwise have been given to the killer (though this is a lot rarer for flammables as the damage tick is fairly low (usually 5)). This can be seen in the demonstration below, where a Dragon does not gain any experience from destroying a Black Market:

FLAME_NO_XP.mp4

This is a counterpart to #1527 and fixes the same issue but for flame weapons; essentially making experience yields consistent for units directly killed by flame damage weapons. It pretty much exclusively affects the Dragon Tank's primary weapon and does not affect experience yields for flame damage dealt via projectile detonation OCLs such as firewalls or firestorms.

[xezon]

I expect this is fine and needs no configurability.

[xezon]

We can merge this together with #1527