feat: added laber for header dropdown btn

Author: vladislavkeblysh

src/learning-header/AuthenticatedUserDropdown.jsx

@@ -37,7 +37,7 @@ const AuthenticatedUserDropdown = ({ intl, username }) => {
 
   return (
     <Dropdown className="user-dropdown ml-3">
-      <Dropdown.Toggle variant="outline-primary">
+      <Dropdown.Toggle variant="outline-primary" aria-label={intl.formatMessage(messages.userOptionsDropdownLabel)}>
         <FontAwesomeIcon icon={faUserCircle} className="d-md-none" size="lg" />
         <span data-hj-suppress className="d-none d-md-inline">
           {username}

src/learning-header/messages.js

@@ -36,6 +36,11 @@ const messages = defineMessages({
     defaultMessage: 'Sign Out',
     description: 'The label for the user menu Sign Out action.',
   },
+  userOptionsDropdownLabel: {
+    id: 'header.menu.aria-label',
+    defaultMessage: 'User Options',
+    description: 'The aria-label for the user options dropdown.',
+  },
 });
 
 export default messages;