fix(lab): clear references to a task key after deleting a task

[eatyourgreens]

A small helper function which iterates through workflow.tasks and deletes references to a given task key. It's called after deleting a task, so that other tasks no longer link to the deleted task.

• Fixes Deleting a task doesn't clean up references to the deleted task key #7011.
• Fixes Task order not reflecting Lab choice + freezing workflow front-end-monorepo#5807.

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: 56.962% (+0.01%) from 56.948%
when pulling 61a99e0 on eatyourgreens:fix-next-task
into 2d0f81a on zooniverse:master.

[eatyourgreens]

Both the new function and its test were written almost entirely by Copilot. It needs supervision, but seems to be very good at small tasks like this.

[shaunanoordin]

Request: changes to app/pages/lab/workflow.jsx should also be replicated, if possible, on app/pages/lab-fem/workflow.jsx

[eatyourgreens]

Done, and rebased to the latest changes on the main branch.