Hello,
Till now there is no alternative option to get Google chart library Locally
Below part Mentioned in above link in FAQ
Que : Can I download and host the chart code locally, or on an intranet?
Ans : Sorry; our terms of service do not allow you to download
and save or host the google.charts.load or google.visualization code. However, if you don't need the interactivity of Google Charts,
you can screenshot the charts and use them as you wish.
You can use alternative libraries
Official Demo Video
Regards
Chandrabhan