fix(lab): prevent tasks linking to themselves

[eatyourgreens]

A second go at fixing this, previously fixed in #5925. Pass the current task key as a prop to NextTaskSelector. Filter the list of tasks to exclude that task key, so that a task can't link back to itself.

This has to be edited in the editors for each individual task type, but I think I got them all.

• Fixes #2512 (for the second time.)

Required Manual Testing

• [ ] Does the non-logged in home page render correctly?
• [ ] Does the logged in home page render correctly?
• [ ] Does the projects page render correctly?
• [ ] Can you load project home pages?
• [ ] Can you load the classification page?
• [ ] Can you submit a classification?
• [ ] Does talk load correctly?
• [ ] Can you post a talk comment?

Review Checklist

• [ ] Does it work in all major browsers: Firefox, Chrome, Edge, Safari?
• [ ] Does it work on mobile?
• [ ] Can you npm ci and app works as expected?
• [ ] If the component is in coffeescript, is it converted to ES6? Is it free of eslint errors? Is the conversion its own commit?
• [ ] Are the tests passing locally and on GitHub Actions?

Optional

• [ ] Have you replaced any ChangeListener or PromiseRenderer components with code that updates component state?
• [ ] If changes are made to the classifier, does the dev classifier still work?
• [ ] Have you resized and compressed any image you've added?
• [ ] Have you added in flow type annotations?
• [ ] Have you followed the Springer guidelines for commit messages?

[coveralls]

coverage: 56.966% (-0.03%) from 56.994% when pulling 24ff284d642c6be291a83cf676c6aae3ce448eae on eatyourgreens:fix-next-task-selector into 408ffca76ef87848ffd23082282606ba2a6b3d6c on zooniverse:master.