Potential fix for code scanning alert no. 3732: Unused variable, import, function or class

Co-authored-by: Copilot Autofix powered by AI <62310815+github-advanced-security[bot]@users.noreply.github.com>

examples/jsm/utils/VolumeMesh.js

@@ -72,7 +72,6 @@ export class VolumeMesh extends Mesh {
 		this.sdfTexture.magFilter = LinearFilter;
 
 		const point = new Vector3();
-		const ray = new Ray();
 		const target = {
 			point: new Vector3(),
 			distance: 0,