fixes the stealth music not changing in delivery charge

This is not fully fixable, because the heist itself doesnt know when to change the intensity, so what i did is make it change by time instead of the objectives changing the intensities (the heist doesnt have objectives that change the intensities).

(stealth 1, 2, 3 will play once, then stealth 4 loops twice, and after that stealth 5 loops infinitely.