Navigate to login page if anonymous room creation is disabled

Known issue: The dialogs background overlay flickers during navigation because the dialog is opened and then closed immediately. To fix this issue, the auth logic would need to be moved to the dialog service or even the component which opens the dialog (ugly) or dialog handling in general would need to be refactored.

This doesn't really have a large impact on the user experience, so I don't think it needs fixing at the moment.