Update FullStory `window._fs_host` Value

[kingkool68]

I started noticing the following errors in my dev console:

Access to script at 'https://www.fullstory.com/s/fs.js' from origin 'xxxxxxx' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.
fs.js:3          GET https://www.fullstory.com/s/fs.js net::ERR_FAILED 404

Looks like window._fs_host = 'www.fullstory.com' needs to be changed to window._fs_host = 'fullstory.com' at https://github.com/DavidWells/analytics/blob/master/packages/analytics-plugin-fullstory/src/browser.js#L57