student account is not disabled when user closes the tab

Steps to reproduce

Login to an instance that is not in exercise mode as a student, then close the tab / kill the browser etc.

What is the current bug behavior?

The student's user account is not disabled when exiting Grady without logging out.

What is the expected correct behavior?

The student's user account should be disabled when the student exits Grady, no matter how.

Possible fixes

Call the logout method in the "unload" event listener in the AutoLogout component.