[MC-234737] Typo in exception message: "EmtyPoolElement"

The bug

While reproducing MC-227202 and ~~MC-227945~~, a frequent error is logged:

Exception loading structure piece with id minecraft:jigsaw
java.lang.IllegalStateException: Invalid call to EmtyPoolElement.getBoundingBox, filter me!

This is a typo, the word is missing a "p". It is supposed to be EmptyPoolElement.

Analysis

There's a typo in the exception message.

net.minecraft.world.level.levelgen.feature.structures.EmptyPoolElement.java (Mojang mappings, 1.18-pre1)

...
@Override
    public BoundingBox getBoundingBox(...) {
        throw new IllegalStateException("Invalid call to EmtyPoolElement.getBoundingBox, filter me!");
    }
...