Change user triggering delete action

https://github.com/weaveworks/clusters-config/actions/workflows/delete-cluster.yaml

I could see it is set to Saeed 🤔 

<img width="387" alt="Screenshot 2023-08-02 at 08 40 48" src="https://github.com/weaveworks/clusters-config/assets/12957664/80786ee6-b256-4ac9-abdf-650d2dcc4850">
