Bug: Re-enrichment duplicates work experiences creating the same employments without dates

[sausage-todd]

Changes proposed ✍️

What

🤖 Generated by Copilot at 0821bbc

This pull request improves the member enrichment feature by adding transaction management, enhancing the organization data, and fixing the data format and deduplication issues. It affects the memberEnrichmentCacheRepository, memberRepository, memberService, and memberEnrichmentService modules in the backend/src directory.
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🤖 Generated by Copilot at 0821bbc

We're the crew of the MemberEnrichmentService
We update the profiles with skill and finesse
We use transactions to keep the data clean
And we cast JSONB to make the orgs seen

Why

How

🤖 Generated by Copilot at 0821bbc

• Add transaction management to database queries using SequelizeRepository class (link, link, link, link, link, link, link, link, link)
• Modify organizations array format and deduplication logic to include member organization relation data (link, link, link, link, link)
• Add delete query to avoid duplicate work experiences in memberOrganizations table (link)
• Refresh result variable with updated member data after work experience upserts (link)
• Add condition to return null if enrichmentData is falsy (link)
• Add console.log statements for debugging purposes (link, link, link)

Checklist ✅

• Label appropriately with Feature, Improvement, or Bug.
• Add screehshots to the PR description for relevant FE changes
• New backend functionality has been unit-tested.
• API documentation has been updated (if necessary) (see docs on API documentation).
• Quality standards are met.