Error with deleted user authorization

[zqian]

There are two cases related to deleted user authorization:

1. if the user removes the authorization for CAE in Canvas but the token is still active
2. if the user's token expires and the authorization is removed, but the application is still open and the user tries to add or remove a tool

Handling these other cases may require some custom middleware and perhaps redirect logic on the frontend.

generated from #208

[jonespm]

These are both edge cases that involve someone going and removing authorization.

We haven't noticed any of these types of failures in the logs for our other apps.

I think it's pretty unusual for someone to go in and remove authorization but we still should make sure this works, probably more 1 because 2 would require them to actually have the tab open in a separate window where they removed the authorization.

The workaround currently would be for an admin to go in the UI and remove their token if we got a ticket with this problem.