Summary:
Mobs do not play the sound of item drops. This doesn't compare to the fact that you can hear mobs collecting items and equipping armor.

Steps to reproduce:

1. Take a stack of some items.
2. Close your inventory and take the item into your hand.
3. Drop items a couple of times.
4. Summon a piglin.
5. Give the piglin gold ingot.
6. Wait until the piglin drops an item.

Observed results:
When dropping items, piglins have no sound, but you can hear it when you drop an item yourself.

Expected results:
You will hear the sound of the piglin dropping items, as well as collecting items.

Notes:
The behavior of this sound cannot be compared with Java, since it does not exist, when a player drops items.