feat: Add toggleBookmarksSidebar function to ZenUIManager

src/browser/base/content/ZenUIManager.mjs

@@ -15,5 +15,10 @@ var gZenUIManager = {
     return "10000000-1000-4000-8000-100000000000".replace(/[018]/g, c =>
       (+c ^ crypto.getRandomValues(new Uint8Array(1))[0] & 15 >> +c / 4).toString(16)
     );
-  },  
+  },
+  
+  toogleBookmarksSidebar() {
+    const button = document.getElementById('zen-bookmark-button');
+    SidebarController.toggle('viewBookmarksSidebar', button);
+  },
 };