Alerting: Template group editor: Alert ".Status" always "resolved" regardless of payload

### What happened? Payload contains one alert with the status "firing", but the preview always shows the status "resolved". <img width="1879" height="1072" alt="Image" src="https://github.com/user-attachments/assets/ba6da5c4-9d2c-4a4c-81b2-8132d09f6469" /> ### What did you expect to happen? Preview should show the status from the payload. ### Did this work before? Not sure. ### How do we reproduce it? 1. Create a template with: ``` {{ define "grafana.issue.demo" -}} {{ (index .Alerts 0).Status }} {{ .Status }} {{- end -}} ``` 2. Use the demo payload with the status "firing" ``` [ { "status": "firing", "annotations": { "summary": "Instance instance1 has been down for more than 5 minutes", "description": "The instance instance1 has been unreachable for more than 5 minutes, indicating a potential service outage." }, "labels": { "alertname": "InstanceDown", "instance": "instance1", "severity": "critical", "service": "service1", "environment": "production" }, "startsAt": "2025-12-04T20:11:17.810Z", "endsAt": "2025-12-05T20:16:17.810Z", "fingerprint": "a5331f0d5a9d81d4", "generatorURL": "http://grafana.com/alerting/grafana/cdeqmlhvflz40f/view" } ] ``` 3. View the preview ### Is the bug inside a dashboard panel? _No response_ ### Environment (with versions)? Grafana: grafana-v12.3.0 Client OS: Window 11 Browser: Edge 142.0.3595.94 ### Grafana platform? Docker ### Datasource(s)? _No response_