show scrollbar for sidebar (#6839)

* show scrollbar for sidebar

* Update src/components/Sidebar/Sidebar.scss

* Update src/components/Sidebar/Sidebar.scss

Author: chenxsan

src/components/Sidebar/Sidebar.scss

@@ -17,14 +17,8 @@
   padding: 1.5em;
   position: sticky;
   top: -1px;
-  overflow: scroll;
+  overflow-y: auto;
   max-height: 100vh;
-  // To hide scrollbar in Firefox
-  scrollbar-width: none;
-  // To hide scrollbar in Chrome
-  &::-webkit-scrollbar {
-    width: 0 !important;
-  }
 }
 
 .sidebar__group {