Updating the example's ts logic

Added an explicit if (!instance) return

Author: 0mar-K

playground/forms/custom-toolbar-radio-button/index.ts

@@ -8,6 +8,8 @@ const item = {
   id: "add-radio-group",
   title: "Add Radio Group",
   onPress: async () => {
+    if (!instance) return;
+
     const radioWidget1 = new window.NutrientViewer.Annotations.WidgetAnnotation(
       {
         id: window.NutrientViewer.generateInstantId(),
@@ -54,7 +56,7 @@ const item = {
         defaultValue: "1",
       },
     );
-    await instance!.create([radioWidget1, radioWidget2, formField]);
+    await instance.create([radioWidget1, radioWidget2, formField]);
   },
 };