Boss electric wall isn't replaced

[ithinkandicode]

Looks like it's a material (M_ElectricWall), or a shader or something

So while our code does replace the sprites, this doesn't affect this material.

Perhaps we need to target the M_ElectricWall material, then update its mainTexture (aka _MainTex)?

https://docs.unity3d.com/2019.4/Documentation/ScriptReference/Material.html
https://docs.unity3d.com/2019.4/Documentation/ScriptReference/Material-mainTexture.html