Remove unnecessary g-menu-stackable-scrollable (#24462)

Fix #24460

That's a mistake but ..... no idea why I wrote so ... remove it.

Author: wxiaoguang

templates/user/dashboard/navbar.tmpl

@@ -1,5 +1,5 @@
 <div class="dashboard-navbar">
-	<div class="ui secondary stackable menu g-menu-stackable-scrollable">
+	<div class="ui secondary stackable menu">
 		<div class="item">
 			<div class="ui floating dropdown jump">
 				<span class="text truncated-item-container">

web_src/css/base.css

@@ -2803,19 +2803,6 @@ table th[data-sortt-desc] .svg {
   height: 15px;
 }
 
-.g-menu-stackable-scrollable {
-  overflow-y: hidden;
-  overflow-x: auto;
-}
-
-@media (max-width: 767.98px) {
-  /* also respect Fomantic's "stackable" definition, use the same breakpoint to reset our styles */
-  .g-menu-stackable-scrollable {
-    overflow-x: unset;
-    overflow-y: unset;
-  }
-}
-
 .color-text-light-2 {
   color: var(--color-text-light-2);
 }