API Feature Request - Thread-safe hologram visibility logic

[IllusionTheDev]

By default, attempting to force-hide a hologram in the main thread results in an exception being thrown, as the HologramHideEvent needs to be called async.

Proposed solution: Allow the event to be called both sync and async.
Alternative solution: Rework the API to return a CompletableFuture and handle the logic async (shouldn't be needed, it's just sending a packet).