Improved session exit behavior

Prior to this update, when leaders or presenters clicked the x icon on the Cornerstone Classroom App window and if there were no recordings to publish or no event termination or email options configured, the App exited without displaying any confirmation message. Similarly, when participants clicked the x icon, the App exited without displaying any confirmation message.

This update improves the usability of the session exit behavior of the Cornerstone Classroom App.

Now, when participants click the x icon, the App always displays the "Do you really want to exit the session?" dialog box.