Update to use new taxonomy schema

[diversemix]

Description

Changes the function get_schema_for_org to use the new schema

Proposed version

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Type of change

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How Has This Been Tested?

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Reviewer Checklist

• The PR represents a single feature (small drive-by fixes are also ok)
• The PR includes tests that are sufficient for the level of risk
• The code is sufficiently commented, particularly in hard-to-understand areas
• Any required documentation updates have been made
• Any TODOs added are captured in future tickets
• No FIXMEs remain

[linear]

PDCT-944 Change `app/repository/metadata.py`to not use new Corpus relations

[katybaulch]

nice one 🦖