Notify on OpenSearch Sync Failures in Harvester

[FuhuXia]

After each record update in the harvester, a sync step sends index updates to OpenSearch. If this step fails, the process logs an error and continues, leaving the database and OpenSearch out of sync. Although a nightly GitHub task attempts to reconcile them, such failures should trigger alerts so developers can investigate promptly rather than allowing issues to go unnoticed.

• Log messages should clearly indicate when an OpenSearch sync fails.
• Each failed record should generate a single log entry to quantify impact.
• New Relic should send alerts to the Slack channel when failures exceed a defined threshold.