Fix skeleton helper

[DanielBelmes]

Remap a bone name to hips so that skeletonHelper works.

#9079

Explanation

🤖 Generated by Copilot at da3d164

• Add a fallback mapping for bones that are not found in the mixamoVRMRigMap (link)
• Define the hipRigMap object in packages/engine/src/avatar/AvatarBoneMatching.ts (link)

🤖 Generated by Copilot at da3d164

We're sailing on the virtual sea, with avatars of all kinds
But some of them are out of sync, their bones don't match their minds
So we need a fallback map, for those who use Mixamo
We'll align them with the VRM, and make them good to go