refactor(classifier): use a map for survey task characteristics

[eatyourgreens]

Refactor survey task characteristics to use a Map, rather than types.frozen. This should make the code easier to read (and hopefully maintain.)

Please request review from @zooniverse/frontend team or an individual member of that team.

Package

• lib-classifier/plugins/tasks/survey

Linked Issue and/or Talk Post

• follows on from fix(classifier): surveyTask.alwaysShowThumbnails must be a boolean #6085

How to Review

I tested this in the storybook, but any survey task project should work, as long as it has characteristic filters.

Checklist

PR Creator - Please cater the checklist to fit the review needed for your code changes.
PR Reviewer - Use the checklist during your review. Each point should be checkmarked or discussed before PR approval.

General

• Tests are passing locally and on Github
• Documentation is up to date and changelog has been updated if appropriate
• You can yarn panic && yarn bootstrap or docker-compose up --build and FEM works as expected
• FEM works in all major desktop browsers: Firefox, Chrome, Edge, Safari (Use Browserstack account as needed)
• FEM works in a mobile browser

General UX

Example Staging Project: i-fancy-cats

• All pages of a FEM project load: Home Page, Classify Page, and About Pages
• Can submit a classification
• Can sign-in and sign-out
• The component is accessible
  • Can be used with a screen reader BBC guide to VoiceOver
  • Can be used from the keyboard WebAIM guide to keyboard testing
  • It is passing accessibility checks in the storybook.

Refactoring

• The PR creator has described the reason for refactoring
• The refactored component(s) continue to work as expected

[coveralls]

coverage: 79.282% (-0.04%) from 79.323%
when pulling 875b67d on eatyourgreens:refactor-survey-task-characteristics
into 9a7a630 on zooniverse:master.