Remove duplicate registration of KHR_interactivity

[ryantrem]

This was recently added near the end of the file, but it was already being registered on line 49. This resulted in a warning in the console about the double registration.

[bjsplat]

Please make sure to label your PR with "bug", "new feature" or "breaking change" label(s).
To prevent this PR from going to the changelog marked it with the "skip changelog" label.

[bjsplat]

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[bjsplat]

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[bjsplat]

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