fix USDZExporterOptions type to be able to build

packages/model-viewer/src/features/ar.ts

@@ -27,6 +27,13 @@ let isSceneViewerBlocked = false;
 const noArViewerSigil = '#model-viewer-no-ar-fallback';
 
 export type ARMode = 'quick-look'|'scene-viewer'|'webxr'|'none';
+// TODO PR to be done in https://github.com/three-types/DefinitelyTyped/blob/master/types/three/examples/jsm/exporters/USDZExporter.d.ts
+// once the patch to be able to {ar: undefined} is merged in three.js repo.
+interface USDZExporterOptions {
+    ar: undefined | { anchoring: { type: 'plane' }, planeAnchoring: { alignment: 'horizontal' | 'vertical' } };
+    quickLookCompatible?: boolean;
+    maxTextureSize?: number;
+}
 
 const deserializeARModes = enumerationDeserializer<ARMode>(
     ['quick-look', 'scene-viewer', 'webxr', 'none']);
@@ -442,7 +449,7 @@ configuration or device capabilities');
 
       // QuickLook places the model on both floor and wall correctly when
       // the usdz doesn't contain the anchoring and planeAnchoring properties.
-      const usdzOptions = this.arPlacement === 'wall' ? {ar: undefined} : {
+      const usdzOptions: USDZExporterOptions = this.arPlacement === 'wall' ? {ar: undefined} : {
         ar: {
           anchoring: {type: 'plane'},
           planeAnchoring: {