Fix regression in GltfLoader for handling Draco _BATCHID

[ptrgags]

While working on #10018, I noticed that this Sandcastle was failing to load draco tiles.

I tracked it down, it was a regression in #10008. Only the ModelComponents.Attribute.semantic should be renamed, not the semantic for the vertex buffer loader.

@lilleyse could you review?

[cesium-concierge]

Thanks for the pull request @ptrgags!

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Reviewers, don't forget to make sure that:

• Cesium Viewer works.
• Works in 2D/CV.