Pet Transfer

Updated the mod to 1.21.4.

Thanks to chimericdream for updating the mod to 1.19!

Changelog:

• Add the "creative contract", which is unobtainable but allows you to create a contract from any tamed creature (even if you don't own it).

Changelog:

• Add a mixin to MobEntity.interactWithItem() to fix support for donkeys

Changelog:

• Fix a bug caused by using "==" instead of .equals() that caused pets to return incorrect ownership status.

Changelog:

Adds support for horses (and anything that extends HorseBaseEntity), thanks to deirn for the report!