Update webgpu_sandbox.html

Remove unused import.

examples/webgpu_sandbox.html

@@ -22,7 +22,6 @@
 			import AttributeNode from './jsm/renderers/nodes/core/AttributeNode.js';
 			import FloatNode from './jsm/renderers/nodes/inputs/FloatNode.js';
 			import Vector2Node from './jsm/renderers/nodes/inputs/Vector2Node.js';
-			import Vector3Node from './jsm/renderers/nodes/inputs/Vector3Node.js';
 			import ColorNode from './jsm/renderers/nodes/inputs/ColorNode.js';
 			import TextureNode from './jsm/renderers/nodes/inputs/TextureNode.js';
 			import UVNode from './jsm/renderers/nodes/accessors/UVNode.js';