CORS issue when requesting flutter website files from DevTools

[kenzieschmoll]

Issue when requesting survey json file:

Access to XMLHttpRequest at 'https://flutter.dev/f/dart-devtools-survey-metadata.json' from origin 'http://127.0.0.1:9109' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.

Additionally, when developing the website and hosting through docker, we are seeing a CORS error when requesting the DevTools release notes files. So we get a CORS error when requesting the release notes markdown files through the localhost:4002 url, but we do not see the CORS error when requesting through the flutter.dev url.