Changes pending review notification workflow config to run on workflow_dispatch event (#14177)
Changes pending review notification workflow config to run on workflow_dispatch event (#14177)

* Adds pending review notification workflow

* CHanges in workflow for testing

* Adds new secret token

* Removes permissions

* Add test mode flag

* Address self review comment

* Fix typo

* Fix lint issue

* Adds failure notification step

* Adds oppia-web in message

* Add newline

* Removes extra newline

* Updates message

* Update template

* Adds workflow_dispatch

* Address review comment
oppia/oppia,oppia/oppia,brianrodri/oppia,kevinlee12/oppia,oppia/oppia,brianrodri/oppia,kevinlee12/oppia,brianrodri/oppia,brianrodri/oppia,oppia/oppia,kevinlee12/oppia,oppia/oppia,brianrodri/oppia,kevinlee12/oppia,kevinlee12/oppia