Mob AI Tweaks

-Rewritten the code the Ender Dragon uses to respawn End Crystals.

-The Ender Dragon now remembers where all the End Crystals are when leaving and entering a world during her fight.

-The saved positions of destroyed End Crystals are now saved via NBT data.

-Fixed the client hitbox position of the End Crystals being desynced when respawned unless you reload the world, this caused End Crystals to become indestructible.

-Fixed Grappling Bobber enchantment being able to grapple into the air if the mob it is hooked onto dies. Now, the hook snaps if the mob it is attached to dies.