Fix Netlify Edge Functions test suite and re-enable in CI

[tony-sull]

What version of astro are you using?

1.0.0-beta.46

Are you using an SSR adapter? If so, which one?

Netlify Edge

What package manager are you using?

pnpm

What operating system are you using?

Mac

Describe the Bug

Netlify Edge Functions were disabled in #3631, it looks like they'll need a little love to run reliably in the CI test runner

Link to Minimal Reproducible Example

na

Participation

• [X] I am willing to submit a pull request for this issue.