Fix empty git repo handling logic and fix mobile view (#33101) (#33102)

Backport #33101 and UI fix from main (including #33108)

web_src/css/modules/navbar.css

@@ -66,7 +66,8 @@
     align-items: stretch;
   }
   /* hide all items */
-  #navbar .item {
+  #navbar .navbar-left > .item,
+  #navbar .navbar-right > .item {
     display: none;
   }
   #navbar #navbar-logo {