[1.19.2] Lack of null check for itemStack in SpawnEggUseSoundMixin.

[bconlon1]

This issue was originally opened on The Aether's repository here: The-Aether-Team/The-Aether#1831.

Essentially, it seems Auditory is missing a check for itemStack != null before calling itemStack.getItem() in this mixin method. The issue with this is that in the original EntityType#spawn() method, itemStack is marked as @Nullable, meaning its not always expected to be non-null. So, Auditory crashes if null is passed by another mod into this parameter.

[Sydokiddo]

Will be fixed in Auditory's rewrite!