fix expected behavior (webgpu based) (#21692)

examples/jsm/renderers/webgl/nodes/WebGLNodes.js

@@ -35,7 +35,7 @@ Material.prototype.onBuild = function ( parameters, renderer ) {
 	fragmentShader = addCodeAfterSnippet( fragmentShader, '#include <color_fragment>',
 		`#ifdef NODE_COLOR
 
-			diffuseColor *= NODE_COLOR;
+			diffuseColor = NODE_COLOR;
 
 		#endif` );