Keep vulnerability_statistics.traversal_ids in sync

Why are we doing this work

As part of #512592 (closed) we're adding a new traversal_ids column to the vulnerability_statistics table. This column must be kept in sync with the projects and namespaces tables. To do so, we register new workers that respond to ProjectTransferedEvent and GroupTransferedEvent. Alternatively, we can reuse existing workers that are already registered for these events. See register_threat_insights_subscribers.

Relevant links

• #512592 (closed)

Non-functional requirements

• Documentation
• Feature flag
• Performance: SQL queries
• Testing: specs

Implementation plan

Very similar to the current implementation of UpdateNamespaceIdsOfVulnerabilityReadsWorker

Also refer to #513028 (comment 2295959180)

Verification steps

• Move a test project that has vulnerabilities and vulnerability_statistics record.
• Check the log, and look for a successful "update traversal ids" job.
• Check the database, and see whether traversal_ids has been updated for the project_id.