Zombies' equipped items on the body and saddle slots are not dropped according to `drop_chances` when converting to drowned

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

When such a conversion occurs, the drowned retains any body or saddle or item given to the zombie via commands. Per the standard outlined in MC-311623, it would be expected that the items a drowned cannot make use of (body and saddle) would be dropped according to drop_chances (preferably reflecting the chance value exactly), while the remaining items (hands, armor) would be retained by the drowned (as currently happens).

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. Find or set up some water

2. /summon minecraft:zombie ~ ~ ~ {DrownedConversionTime:20,equipment:{saddle:{id:saddle}},drop_chances:{saddle:2f}}

3. Once the zombie converts, /data get entity @n[type=minecraft:drowned] equipment
   ❌ The saddle has been retained

Expected behavior

The saddle would be dropped on the ground since the drowned cannot make use of it.