Issue with Holograms Improperly being deleted.

[dpvb]

Had an issue where using /sa stop to stop the game, and start it back up again that sometimes I would get NPE when I would have HackableChests placed in the Arena.

This was further shown that if the game was stopped, but you were in the Arena, holograms were also showing up on the regular chests which they shouldnt when the game is inactive.

This should be investigated more thoroughly.

[ms5984]

Nullability of the LootableChest.hologram field is not well-defined and leads to accidental operation on a null reference. We need to gate the hologram.delete() call with a null-check.