Get PR preview to work correctly

[edwardchalstrey1]

Currently when you create a PR to main, there will be a preview generated e.g. https://alan-turing-institute.github.io/astroemulate/pr-preview/pr-13/ and a comment with this link will get added to the PR

As you can see, unfortunately because this get's redirected to https://www.autoemulate.com/pr-preview/pr-13/ there is a 404 error.

I don't know whether the preview was not generated correctly or we are just unable to view it

See one attempt to solve this commented out at the bottom of Layout.astro