GltfLoader: fix too generic assigment of light decay (#30411)

Co-authored-by: Samuel Rigaud <srigaud@duodisplay.com>

examples/jsm/loaders/GLTFLoader.js

@@ -600,8 +600,6 @@ class GLTFLightsExtension {
 		// here, because node-level parsing will only override position if explicitly specified.
 		lightNode.position.set( 0, 0, 0 );
 
-		lightNode.decay = 2;
-
 		assignExtrasToUserData( lightNode, lightDef );
 
 		if ( lightDef.intensity !== undefined ) lightNode.intensity = lightDef.intensity;