chore: add identifiers to some upgrade links/buttons (#1686)

src/courseware/course/course-exit/Footnote.jsx

@@ -3,7 +3,7 @@ import PropTypes from 'prop-types';
 import { FontAwesomeIcon } from '@fortawesome/react-fontawesome';
 
 const Footnote = ({ icon, text }) => (
-  <div className="row w-100 mx-0 my-4 justify-content-center">
+  <div id="celebration-footnote-wrapper" className="row w-100 mx-0 my-4 justify-content-center">
     <p className="text-gray-700">
       <FontAwesomeIcon icon={icon} style={{ width: '20px' }} />&nbsp;
       {text}

src/courseware/course/course-exit/UpgradeFootnote.jsx

@@ -20,6 +20,7 @@ const UpgradeFootnote = ({ deadline, href }) => {
 
   const upgradeLink = (
     <Hyperlink
+      id="upgrade-link"
       style={{ textDecoration: 'underline' }}
       destination={href}
       className="text-reset"