Fix auto_pickup.sc for new versions

[WesleyJ-128]

At some point (potentially 1.20.6 when the component system was added), the nbt contained in item entities was changed to include the count of the items. This breaks auto_pickup.sc, as it checks for the nbt of the items to match, which will not happen when the counts are unequal— my solution is to use replace() to remove the count field from the nbt before comparing. This should be backwards-compatible as replace() will do nothing if the match is unsuccessful.

[WesleyJ-128]

As the commit message notes, the regex fix deletes the counts in shulker box contents as well. To fix this, I copy the nbt of the inventory item and modify its count to match that of the picked-up item, then compare if the modified nbt equals the picked-up item's nbt. Additionally, the nbt is checked for a count field before it is modified to retain backwards compatibility.

[WesleyJ-128]

Fixed another issue with the stackableShulkerBoxes carpet rule— the pickup script would stack filled boxes together, which is incorrect. There is now a change in behavior from previous versions; the script will automatically stack empty boxes, but this is convenient and empty boxes can be stacked in the inventory anyway. If original functionality is desired, remove && has(item_nbt, 'components') from line 45.