[Bugfix] Fix Item Delta capacity mismatch with Items array

[kphoenix137]

Fixes: #8339

Items generated on the floor in the dungeon remain in the level delta with a flag set to prevent these items from being respawned after they are picked up. As a result, the available capacity of the delta is lower than that of the Items array, meaning after a certain number of items are added to the Items array, items start failing to be added to the delta, resulting in the loss of these items when the delta is cleared and reloaded.

This PR fixes that by doubling the capacity of the delta. Therefore, in theory, if the game were to spawn the maximum number of pregenerated items and hit the max capacity of the Items array, the player could pick up all items, and then drop items to fill the entire array again, and no items will be lost.