Mooshrooms' equipment is deleted when converting to cows

Since it was requested that MC-311623 be split up, this report covers equipment transfer when a mooshroom converts to a cow.

When such a conversion occurs, any equipment given to the mooshroom via commands is simply deleted. Per the standard outlined in MC-311623, it would be expected that the items a cow cannot make use of (all equipment slots) would be dropped according to drop_chances (preferably reflecting the chance value exactly).

This “bug” has basically no impact on the game, so I would not really mind if this were to be designated Works As Intended, Won’t Fix or Invalid. However, should other equipment transfer be fully implemented according to the MC-311623 standard, the reason for the inconsistency may be difficult to describe.

To reproduce

1. /summon minecraft:mooshroom ~ ~ ~ {equipment:{head:{id:chainmail_helmet}},drop_chances:{head:2f}}

2. Shear the mooshroom

3. /data get entity @n[type=minecraft:cow] equipment
   ❌ The helmet has been deleted

Expected behavior

The helmet would be dropped on the ground since the cow cannot make use of it.