Geyser Tower update

[WindStrike72]

Another RNG tower that can be inconsistent, though twould rather not apply the same fix as Quake. Instead of going for proc chance, make the ability proc every time. I'mma bump up the explosion delay time for this though:

• When the target dies, all the explosions still occur just like before, but for each extra stack on the target that went off, increase the damage dealt by say 100 / 500 / 2500 (fear my arbitrary numbers).
• For example, say the explosion normally deals 500 damage. However, on a target that died, it had 3 stacks, so all the explosions deal 700 instead of 500. Total area damage being 2100 instead of 1500.
• Also make it so this tower shoots the lowest HP creep.

[WindStrike72]

Applied alt fix via #1971fd6