Summary

• Adds learner_needs field to content node API
• Adds response regularization to ensure that older public APIs have their learner_needs field backfilled to [] to ensure a consistent data structure on the frontend
• Handle etag being missing from response headers as an edge case
• Update and add tests for this
• Flyby - fix flakey assertion for files by explicitly sorting.

References

Fixes #12687
Fixes one of the flaky tests remaining in #8255

Reviewer guidance

Does the learner_needs field properly appear in both internal and public API endpoints now? Do the test changes make sense.

Testing checklist

• Contributor has fully tested the PR manually
• If there are any front-end changes, before/after screenshots are included
• Critical user journeys are covered by Gherkin stories
• Critical and brittle code paths are covered by unit tests

PR process

• PR has the correct target branch and milestone
• PR has 'needs review' or 'work-in-progress' label
• If PR is ready for review, a reviewer has been added. (Don't use 'Assignees')
• If this is an important user-facing change, PR or related issue has a 'changelog' label
• If this includes an internal dependency change, a link to the diff is provided

Reviewer checklist

• PR is fully functional
• PR has been tested for accessibility regressions
• External dependency files were updated if necessary (yarn and pip)
• Documentation is updated
• Contributor is in AUTHORS.md