Horse Armor does not appear on Zombie Horses when using a resource pack with a format version of 1

1. Download the minecraft classic textures

2. Create a world and obtain horse armor and a zombie horse spawn egg

3. Tame the zombie horse and equip it with armor
   
   
   Observed results
   Zombie horses do not have the texture of the equipped armor
   
   Expected results
   
   Zombie horses should have the armor texture of the equipped armor
   
   
   
   
   
   
   None of the Horse Armor can appear on the Zombie horse you can equip it but it is invisible.

Pictures are below.

I kept it to just Netherite and diamond armor pictures as I figured any extra would be redundant, but it applied to all of the Horse Armor.

This is on a regular world without Experimental features, nor recourse packs and behavior packs, however the bug does apply to worlds with experimental features.