GitHub CSP blocking browser extension requests to local instance

Created by: ryan-blunden

To reproduce, launch a local Sourcegraph and lang server, point the browser extension at your local instance, then try getting code intelligence to work. This seems to have happened to @KattMingMing today and I was able to reproduce the issue on @dadlerj's local instance.

When browsing GitHub with the browser extension installed, after an indeterminate amount of time, requests from the browser extension from the contents script start failing due to CSP issues.

It's triggered when the CSP has a different frame-src value.