Resolve "Fix exclusive lease usage in transaction for app/services/ci/retry_job_service.rb"

What does this MR do and why?

This MR removes a temporary workaround regarding transactions inside the retry job service. The retry logic is now wrapped in build.run_after_commit. This ensures that the retry logic is only executed after the database transaction is successfully committed, improving consistency and avoiding retrying jobs while the transaction is still open.

See issue: #441525 (closed)