fix: guard against duplicate TouchBarItem IDs (#22644)

lib/browser/api/touch-bar.js

@@ -51,13 +51,25 @@ class TouchBar extends EventEmitter {
         item.child.ordereredItems.forEach(registerItem)
       }
     }
+
+    const idSet = new Set()
     items.forEach((item) => {
       if (!(item instanceof TouchBarItem)) {
         throw new Error('Each item must be an instance of TouchBarItem')
       }
+
+      if (!idSet.has(item.id)) {
+        idSet.add(item.id)
+      } else {
+        throw new Error('Cannot add a single instance of TouchBarItem multiple times in a TouchBar')
+      }
+    })
+
+    // register in separate loop after all items are validated
+    for (const item of items) {
       this.ordereredItems.push(item)
       registerItem(item)
-    })
+    }
   }
 
   set escapeItem (item) {