Scheduler uses stale flow revision for existing triggers after flow update

Describe the issue

The fix for #15281 ("Scheduler uses stale flow revision for existing triggers after flow update") was merged on 2026-03-31 via #15286 (ac0c640), but it was never backported to the 1.3 LTS line.

We are running 1.3.34 and hit the exact symptom described in #15281: a flow updated with task-only changes keeps executing the previous revision indefinitely. See the original issue for the reproducer and full details.

Impact

This is particularly painful with GitOps / CI-driven deployments, where flows are pushed via the API and task-only changes are by far the most common case. Every such deployment silently runs the previous revision until someone notices and toggles the trigger — there is no error, no warning, and the UI shows the new revision as current.

Environment

• Kestra Version: 1.3.34
• Database backend: PostgreSQL
• Deployment: Kubernetes