Queue stays authenticated after log out

[redshiftzero]

The queue stays authenticated after the user logs out. One can repro this via trying to download a file after you've logged out. This is a similar issue to #178, now re-occurring in the queue.

While this won't be possible after freedomofpress/securedrop#3933 is used in the client, regardless the queue should not attempt to send API requests to the server when the user is offline / not logged in.

One resolution would be to add a logout() method to the ApiJobQueue to update the api_client attribute after logout. This method would then get called by the logout method on the controller.

[redshiftzero]

so in #400 @creviera has a good idea which is to have one single place in the client (ApiJobQueue) that accesses the API. this would prevent issues like this from arising because it would be a single place that has the API token (#385 would also help us as developers reason about the application).

I suggest we:

• first do the less-smart resolution here to resolve this bug (what I suggest in the original ticket, adding a logout() method) so that we can tag a release,
• then do a broader refactor following @creviera's suggestion in What can make an API call [Discussion] #400. We can't do this refactor immediately because we need to finish migrating over the existing API actions to the queue (in progress) as well as decide how to handle the login and sync actions (see my comment here).