Revert Dynamax HP on fainting (#4681)

* Revert Dynamax HP on fainting

Calls UndoDynamax whenever a mon faints to ensure that its HP is reverted and the relevant data is cleared. Updates UndoDynamax to CalculateMonStats after applying the HP reversion to prevent fainted mons from retaining their boosted Max HP until the end of the battle.

* Update src/battle_main.c

---------

Co-authored-by: Alex <93446519+AlexOn1ine@users.noreply.github.com>

src/battle_dynamax.c

@@ -207,6 +207,7 @@ void UndoDynamax(u16 battlerId)
         u16 mult = UQ_4_12(1.0/1.5); // placeholder
         gBattleMons[battlerId].hp = UQ_4_12_TO_INT((GetMonData(mon, MON_DATA_HP) * mult + 1) + UQ_4_12_ROUND); // round up
         SetMonData(mon, MON_DATA_HP, &gBattleMons[battlerId].hp);
+        CalculateMonStats(mon);
     }
 
     // Makes sure there are no Dynamax flags set, including on switch / faint.

src/battle_main.c

@@ -3677,6 +3677,9 @@ const u8* FaintClearSetData(u32 battler)
     gBattleStruct->zmove.active = FALSE;
     gBattleStruct->zmove.toBeUsed[battler] = MOVE_NONE;
     gBattleStruct->zmove.effect = EFFECT_HIT;
+    // Clear Dynamax data
+    UndoDynamax(battler);	
+	
     return result;
 }