[Feature]: PreGainSoul Event

[Lanse505]

Chat from Discord:
https://i.imgur.com/3DuBRiT.png

This would be needed to allow me to check the Pre GainSouls event state of the shard.
This would be used to compare the pre-state to the post-state of the shard.

This means for example that in my use-case that I could say:

Well if the pre-state is a tier 2 with 255 kills, and Tier 3's killRequirement is 256.
Then once it gains souls, it should set the killCount to (256 - 1), to prevent the gem from tiering up.