Some parts of the guardian and elder guardian UV maps are missing texturing

There are open spaces in the UV texture maps for the guardian and elder guardian that do not properly convey to resource pack creators the entirity of some model part faces. Since the faces are left empty, it could be easy to assume the open sections are not part of the model, even if they aren't normally visible in-game. For other models with parts that are not visible on other entities, they are always filled in either with texturing, or simply a blank color. The guardian mobs are a specific and strange exception to this convention (likely due to MC-271509)

Elder Guardian:

Guardian:

Suggested Fix:

Add texture (or even just a vague singular color) to the open spaces in both UV maps. Generally, this is what is done for other texture faces of entities which are not regularly seen in game anyways.

Elder Guardian:

Guardian:

Fixed Textures:

(This fix notably also fixes MC-271371)

Notes:

1. Blocked by: MC-271509

2. This was split off from MC-271371 to avoid two issues reported in one.