Clear Dynamax data when a battler faints

[WillKolada]

Description

Updates FaintClearSetData in battle_main.c to clear Dynamax data when a battler faints.

Issue(s) that this PR fixes

Fixes #4484

Discord contact info

Special K#8400

[WillKolada]

In the process of implementing this fix, I discovered a new bug that this does not address (for some reason). The incoming Pokemon does not take the HP penalty from "un-Dynamaxing" anymore, but the Pokemon that faints retains its Dynamax Max HP boost despite no longer being Dynamaxed. This is reverted upon battle end, thankfully, but it means that if you revive this fainted Pokemon, it'll have double the Max HP. I'll look into this more later, but I'll confess it's a far less glaring issue for my own hack than the HP penalty bug is.

[AlexOn1ine]

In the process of implementing this fix, I discovered a new bug that this does not address (for some reason). The incoming Pokemon does not take the HP penalty from "un-Dynamaxing" anymore, but the Pokemon that faints retains its Dynamax Max HP boost despite no longer being Dynamaxed. This is reverted upon battle end, thankfully, but it means that if you revive this fainted Pokemon, it'll have double the Max HP. I'll look into this more later, but I'll confess it's a far less glaring issue for my own hack than the HP penalty bug is.

Is this a bug that appeared after you added the current fix in this PR?

[WillKolada]

Is this a bug that appeared after you added the current fix in this PR?

I double-checked to be sure, and no, this bug already existed, I just hadn't noticed it until testing this fix.