Fix Canvas3D/Canvas3DGS async imports (#7511)
* Fix Model3D and Model3DUpload to handle async-imports and access the child component's exported method
* Refactoring: reorder the lines to put the related snippets together
* add changeset
* Refactoring
* Disable the undo buttons for Canvas3DGS
* add changeset
* Refactoring to use optional chaining
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