fix: skip critical check without report
The critical SAST follow-up job failed when the upstream scan did not produce gl-sast-report.json.
Exit early with status 0 in that case and emit an empty critical.json so artifact handling remains consistent.
The critical SAST follow-up job failed when the upstream scan did not produce gl-sast-report.json.
Exit early with status 0 in that case and emit an empty critical.json so artifact handling remains consistent.