Add gaia arena check to api

[justliliandev]

This PR adds 2 methods to the api to check if something is currently inside a gaia arena

[williewillus]

Thanks. Can you do the following:

1. Check the lint/format errors
2. Instead of duplicating the logic, change the Botania Doppleganger class to call the API method instead.

[justliliandev]

I wouldn't recommend doing that, as the gaia logic would be as follows:

1. Gaia tick
2. Gaia searches for close Players
3. API check if player is inside arena by looking for nearby gaia guardian entities
4. API check if the player is inside the arena of that guardian

this would result in the guardian looking essentially for itself to disable players.
I've changed the api to use the arena AABB which is used in the player lookup to do the arena check, as this is what is used for looking for nearby players and disabling their flight/sleeping/removing effects

[TheRealWormbo]

We should probably incorporate this change in the 1.21 port.