Feature/pdct 1759 make backend config endpoint focused on corpora not

[annaCPR]

Description

• remove organisations object from the /config endpoint response as it is no longer used

NOTE: do not merge before the FE changes are deployed

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• links to any related issue/ticket
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• details of any dependency updates that are required for this change

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Type of change

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How Has This Been Tested?

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Reviewer Checklist

• DB_CLIENT DEPENDENCY IS ON THE LATEST VERSION
• The PR represents a single feature (small driveby 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]

APP-95 Make backend /config endpoint focused on corpora, not organisations

[odrakes-cpr]

lgtm