GLTFLoader: Honor extras in light definitions. (#24897)

examples/jsm/loaders/GLTFLoader.js

@@ -576,6 +576,8 @@ class GLTFLightsExtension {
 
 		lightNode.decay = 2;
 
+		assignExtrasToUserData( lightNode, lightDef );
+
 		if ( lightDef.intensity !== undefined ) lightNode.intensity = lightDef.intensity;
 
 		lightNode.name = parser.createUniqueName( lightDef.name || ( 'light_' + lightIndex ) );