GLTFLoader: Clean up (#23633)

examples/jsm/loaders/GLTFLoader.js

@@ -2904,15 +2904,7 @@ class GLTFParser {
 
 		if ( this.sourceCache[ sourceIndex ] !== undefined ) {
 
-			return this.sourceCache[ sourceIndex ].then( function ( texture ) {
-
-				return texture.clone();
-
-			} ).catch( function ( error ) {
-
-				throw error;
-
-			} );
+			return this.sourceCache[ sourceIndex ].then( ( texture ) => texture.clone() );
 
 		}