Hoppers do not use minecraft:block.iron.* sounds despite being made of iron

The bug

Hoppers are a block composed mostly of iron. However, despite this, they use generic "metal" sounds for placement, breaking, footsteps and falling, despite the existence of dedicated "iron" sounds as of 25w02a. 

How to reproduce

1. Place/break/walk on iron blocks
2. Place/break/walk on hoppers

Expected results

The exact same set of sounds would be used.

Actual results

Hoppers use the old, incorrect sounds.

How to fix

Make hoppers use the new sounds.