fix: Some skin wearables not rendering in avatar view

[sandrade-dcl]

Fix: decentraland/unity-explorer#7325

Problem

Skin wearables with non-standard skeletons (e.g. "LilDoge" — a dog character) were invisible in avatar view. The root cause was that SetupColors blindly replaced all SkinnedMeshRenderer.bones with the standard humanoid avatar bones array. When a skin has a completely different skeleton (different bone count/structure), this collapsed the mesh to nothing. In WebGL/WASM builds, this also triggered a RuntimeError: divide by zero because Unity's internal rendering code attempted to compute normals/matrices on the collapsed mesh.

Fix

• Separated bone rebinding from color setup — SetupColors now only handles materials, and a new RebindBones method handles skeleton binding. These were mixed responsibilities in a single method.
• RebindBones matches bones by name instead of replacing the entire array. Bones that exist in the avatar skeleton are replaced so they animate together, while bones with no match keep their original transform from the GLB. This ensures skin wearables with custom skeletons render and animate correctly.

[github-actions]

Vercel Preview is ready!

Field	Value
Preview	https://aang-renderer-j0cnx528w-decentraland1.vercel.app
Commit	e64a0077fa7a21b59669963965474cdb7864b431
Logs	https://github.com/decentraland/aang-renderer/actions/runs/22687340113