Earlier quoted context omitted.
You actually can host the Google Analytics JS file locally, though I'm not sure it's an officially supported configuration.
Do you have any resources on doing this?
But you can download it, and host it locally. Just update it periodically. As you can see from the changelog, it only changes every few months: https://developers.google.com/analytics/devguides/collection...
Google actually takes a few days to deploy updates to all of their servers. So a daily script to update it on your server would be fine.