MM-53813: Fix(accessibility): on channels page (#24122)

* fix(accessibility): on channels page

* fix lint and update dynamic-virtualized-list

* fix snapshot and update per feedback

* fix e2e tests

* fix test

---------

Co-authored-by: Mattermost Build <build@mattermost.com>

webapp/channels/src/sass/layout/_sidebar-left.scss

@@ -212,7 +212,7 @@ $sidebarOpacityAnimationDuration: 0.15s;
             margin-left: 0;
             background: none;
 
-            li {
+            div {
                 display: flex;
                 margin-left: 15px;
             }
@@ -753,7 +753,7 @@ $sidebarOpacityAnimationDuration: 0.15s;
         }
     }
 
-    #introTextInvite,
+    #inviteMembersButton,
     #addChannelsCta {
         display: flex;
         width: 100%;