improve: Game unwrapItem function

[jprzimba]

Optimized Game::unwrapItem by minimizing repeated attribute fetches, deferring reads, and simplifying amount handling, without changing behavior.

Charges:

• I avoided repeated readings of attributes: OWNER, AMOUNT, DATE are read once.
• Defer reading of DATE only when isCaskItem(unWrapId) is true.
• I simplified the amount calculation with fallback to 1.
• Maintained existing flow and effects: owner validation, bed check, transformItem, add bed, remove temporary attributes, start decay, restore OWNER, apply hiddenCharges to casks.