Undead mounts use the friendly mobs sound category, which is inconsistent

Zombie horses, camel husks and skeleton horses use the friendly mobs sound category which is inconsistent in how the game treats them, as they are part of the hostile mob cap.

Steps to reproduce the issue:

• Summon any of them and set the “Friendly Mobs“ sound to 0, none of them make a sound.

Expected Result:

• They should use the “Hostile Mobs“ sound, as they are monsters.

Actual Result:

• They use the friendly mobs sound set.