Figure out why two deployments sometime appear on a pull request

On pull request https://github.com/wafer-space/wafer-space.github.io/pull/36 two deployments appeared, one for `pr-preview-36` and one for `pr-preview-20`, see screenshot below;

<img width="1894" height="403" alt="Image" src="https://github.com/user-attachments/assets/1ef1f5c5-789a-4ac2-87b2-c081e36e7554" />

You shouldn't see the deployment for pull request 20 on pull request 36.