[MODORDERS-1402] Add deleteHoldings flag to checkin endpoint and implement holding delete logic

[Saba-Zedginidze-EPAM]

Purpose

[MODORDERS-1402] Add deleteHoldings flag to checkin endpoint and implement holding delete logic

Approach

• Add new request parameter
• Use the new param to determine whether to delete holdings
• Use existing logic for abandoned holdings deletion
• Update tests

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Pre-Review Checklist

• Self-reviewed Code — Reviewed code for issues, unnecessary parts, and overall quality.
• Change Notes — NEWS.md updated with clear description and issue key.
• Testing — Confirmed changes were tested locally or on dev environment.
• Logging: Confirmed that logging is appropriately handled.
• Breaking Changes — Handled all required actions if changes affect API, DB, or interface versions.
  • API/schema changes
  • Interface version updates
  • DB schema changes / migration scripts
• New Properties / Environment Variables — Updated README.md if new configs were added.

[sonarqubecloud]

Quality Gate passed

Issues
1 New issue
0 Accepted issues

Measures
0 Security Hotspots
85.2% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud