Fix dropdown menu header and mobile view (#33108)

![image](https://github.com/user-attachments/assets/3f831c8c-ef87-4282-880a-c2738f3e1d17)

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![image](https://github.com/user-attachments/assets/c4c0519b-cfa6-42b4-bd28-205ee514eb34)

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![image](https://github.com/user-attachments/assets/8624a605-9f2b-4905-9cbc-0af073972874)

web_src/css/modules/navbar.css

@@ -48,7 +48,8 @@
     align-items: stretch;
   }
   /* hide all items */
-  #navbar .item {
+  #navbar .navbar-left > .item,
+  #navbar .navbar-right > .item {
     display: none;
   }
   #navbar #navbar-logo {