Add Google Analytics require to mock-ajs (#13620)
Add Google Analytics require to mock-ajs (#13620)

* Fix errors in gtag installation.

* Update mock-ajs.ts

Co-authored-by: Sean Lip <d7e19930cc1f42c2d0781f4d9e6f1fe5891bf9cf@seanlip.org>
brianrodri/oppia,brianrodri/oppia,kevinlee12/oppia,kevinlee12/oppia,oppia/oppia,kevinlee12/oppia,oppia/oppia,brianrodri/oppia,oppia/oppia,kevinlee12/oppia,oppia/oppia,kevinlee12/oppia,brianrodri/oppia,brianrodri/oppia,oppia/oppia