Display error when Path to PHP CLI is not configured and a task is run

Log in as an admin and go to Site administration > Server > System paths. Set " Path to PHP CLI " to the path to your PHP executable. Go to Site administration > Server > Tasks > Scheduled tasks. Confirm  that there is a "Run now" button for most (if not all) of the tasks. Click " Run now " for the " Forum mailings and maintenance jobs " task. On the confirmation prompt, confirm to run the task. Confirm  that the task executes successfully without any errors (except maybe when the outgoing email settings have not been properly configured and that Moodle can't send email messages. This is fine. The important thing is that the task executes okay.) Go back to the Scheduled tasks page. Open another browser tab and go to Site administration > Server > System paths Remove the value in " Path to PHP CLI ". Back on the Scheduled tasks page, click on " Run now " in any of the tasks listed. Confirm  that you get an error that the path to the PHP CLI can't be found. Click on " Continue ". Confirm  that you are redirected to the System paths page. Set " Path to PHP CLI " to the path to your PHP executable. Go back to the scheduled tasks page. Confirm  that there is a "Run now" button for most (if not all) of the tasks. Open another browser tab and go to Site administration > Security > Site security settings Disable "Allow 'Run now' for scheduled tasks" and Save changes. Back on the Scheduled tasks page, click on " Run now " in any of the tasks listed. Confirm that you get the error: "Sorry, but you do not currently have permissions to do that (Run now)." Click on " Continue ". Confirm that you are redirected to the Scheduled tasks page.