GLTFExporter: Fix missing clearcoat normal map scale. (#28099)

examples/jsm/exporters/GLTFExporter.js

@@ -2639,6 +2639,9 @@ class GLTFMaterialsClearcoatExtension {
 				index: writer.processTexture( material.clearcoatNormalMap ),
 				texCoord: material.clearcoatNormalMap.channel
 			};
+
+			if ( material.clearcoatNormalScale.x !== 1 ) clearcoatNormalMapDef.scale = material.clearcoatNormalScale.x;
+
 			writer.applyTextureTransform( clearcoatNormalMapDef, material.clearcoatNormalMap );
 			extensionDef.clearcoatNormalTexture = clearcoatNormalMapDef;