Classifier: refactor UPP data-fetching with hooks

[eatyourgreens]

Remove data-fetching from the classifier's UPP store and move it into a useProjectPreferences hook instead. Preferences should be fetched when the logged-in user changes. UPP updates are still handled by the store, so the store is updated whenever fresh preferences are received from Panoptes.

This PR builds on the user hooks in #2940, so that should be reviewed first. Following recent bugs, caused by problems with tracking user logged-in status via the UPP store, this shifts user data-fetching from our own home-grown code to SWR, which will refresh preferences in the background while the classifier is in use.

TODO:

• check for undefined auth tokens (not null), which indicates that auth is being checked, or updated for a new user.

Package:
lib-classifier

Review Checklist

General

• Are the tests passing locally and on Travis?
• Is the documentation up to date?

Components

• Has a storybook story been created or updated?
• Is the component accessible?
  • Can it be used with a screen reader? BBC guide to testing with VoiceOver
  • Can it be used from the keyboard? WebAIM guide to keyboard testing
  • Is it passing accessibility checks in the storybook?

Apps

• Does it work in all major browsers: Firefox, Chrome, Edge, Safari?
• Does it work on mobile?
• Can you yarn panic && yarn bootstrap or docker-compose up --build and app works as expected?

Publishing

• Is the changelog updated?
• Are the dependencies updated for apps and libraries that are using the newly published library?

Post-merging

• Did the app deploy to https://frontend.preview.zooniverse.org/projects/:project-name/:owner or https://frontend.preview.zooniverse.org/about?
• Is the new feature working or bug now fixed?
  • Is there a Talk or blog post written to announce the new feature(s)?
• Is the design working across browsers (Firefox, Chrome, Edge, Safari) and mobile?
  • Is this approved by our designer?
• Is this ready for production deployment?

[coveralls]

Coverage decreased (-0.03%) to 82.987% when pulling 54c78a1 on upp-hook into e3c339a on master.

[mcbouslog]

LGTM, tested on Planet Findes BETA with two different staging users and signed out, tutorials loaded or didn't load as expected.

Not for this PR, and more for my understanding than review notes, but I notice the hooks don't have try/catch blocks for .get/.post requests, not sure if that's because not needed or something to consider for future refactor.

[mcbouslog]

👍 consistent with other hooks using SWR, LGTM

[mcbouslog]

✅ loadingState is defined in the ResourceStore model

[eatyourgreens]

One of the advantages of using the useSWR hook is that it includes try/catch for network errors. It returns both data and any error.

const { data, error } = useSWR(key, fetcher, options)

See https://swr.vercel.app/