Phoenix should notify a logged-in user who is attempting to view a logout-required page

[arcanemachine]

If a logged-in user is viewing a stale page from when they were logged out, then that user attempts to navigate to e.g. the login page, the user will be immediatedly redirected to the login-success page (e.g. "/todos/live") without any notification whatsoever. This is bad UX and can be somewhat jarring.

To resolve this issue, an already-logged-in user should be shown a message when they are automatically redirected from such a page.

[arcanemachine]

Fixed by 729cfec