Remove ContentNode filters with no implementation

[jonboiser]

Summary

Removes some filters from the ContentNodeFilter that don't appear to have an implementing method and have been supplanted by other API endpoints.

Reviewer guidance

Does this break anything?

References

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Contributor Checklist

PR process:

• PR has the correct target branch and milestone
• PR has 'needs review' or 'work-in-progress' label
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• 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

Testing:

• Contributor has fully tested the PR manually
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• Critical user journeys are covered by Gherkin stories
• Critical and brittle code paths are covered by unit tests

Reviewer Checklist

• Automated test coverage is satisfactory
• 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

[codecov]

Codecov Report

Merging #7509 into develop will decrease coverage by 0.03%.
The diff coverage is n/a.

Impacted Files	Coverage Δ
kolibri/core/content/api.py	88.71% <ø> (-0.15%)	⬇️
kolibri/utils/logger.py	82.50% <0.00%> (-12.50%)	⬇️