Add confirm dialog to End Session

[MikeWilliams-UK]

Please add a confirmation dialog to the End Session to confirm or abort ending of session as this deletes the session.

[wislerd]

This would be useful to ensure user understands what will happen. Sometimes people end session when they really meant to leave. Another great option might be to limit who can End Session to only the creator or project admin users or something like that to limit accidental session closure.