[OptiFine Parity] PBR Support for Animated Entity Textures

[Thanos1716]

OptiFine applies the PBR from the base texture (e.g. iron_golem_n.png) to animated entity textures as well. With MoreMcmeta however, in order to animate the entity texture it seems to completely disable PBR for the entity.

This becomes apparent in the Patrix resource packs, specifically for the Iron Golem and Warden. In the example below, I have made the iron golem texture completely white as to make the normal and specular maps clearer.

This issue also affects Animatica FoundationGames/Animatica#57

Here is a minimum reproducible example of the issue:
Patrix_1.21_32x_basic_MRE_iron_golem.zip

Steps to reproduce the behavior:

1. Install MoreMcmeta and Iris
2. Install any shader pack that supports LabPBR
3. Install Patrix (or above MRE)
4. Look at an Iron Golem

Below is a comparison using Complementary Shaders on all default settings apart from enabling labPBR in the shader settings:

OptiFine:

MoreMcmeta & Iris (& EMF & ETF but occurs without these)

Which Minecraft versions does this bug affect?
Checked in 1.21.1, likely affects all versions.

Mod loader

• Fabric
  Forge likely affected with Oculus as well.

Resource pack
The original resource pack: https://modrinth.com/resourcepack/patrix-32x