First Aid 1.20.1-1.1 local compatibility patch

Adds the missing SynchedEntityData.hasItem delegation described by First Aid PR #272.
This fixes the Epic Fight stamina incompatibility caused by First Aid replacing the player SynchedEntityData with SynchedEntityDataWrapper.
Intended for Epic Fight 20.14.17 on Minecraft 1.20.1.

v2 (crash fix): the previous wrapper class was compiled against a different Forge API and crashed with
NoSuchFieldError: scaleMaxHealth when a player left a world. Its references to FirstAidConfig$Bool, SimpleChannel,
PacketDistributor#with, DamageDistribution#handleDamageTaken and AbstractDamageablePart#getMaxHealth were repointed to the
1.20.1 API; BoolUtil unboxes the Forge config values. Not launched in Minecraft.
