Stackable Absorption Hearts

Fixed two major bugs:

• Damage to the player is now properly taken into consideration. Previously taking damage would not lower the hidden Absorption value, so when eating another golden apple or when the stack would decrease by one, the old stack value was used. This meant you could lose the entire stack due to damage but you would get it back after the effect duration was up. This is now no longer the case
• When joining a world with a stacked effect, the datapack now properly builds on that stack again. Previously it wouldn't be able to take stacks from previous sessions into account