When app foreground we re-register with Salesforce (if we have a device token and logout was not requested).
On logout we unregister from Salesforce but:
- we no longer do that through a notification because the notification is sent after the logout has completed (and the un-register needs to be done while we are authenticated)
- we no longer use a sendAsynchronousRequest for un-register otherwise the delete (which would be queued) ends up being sent after the revoke refresh token