If you link to it directly from your code then yes, unless you're willing to pay Grafana for a commercial license (assuming they offer one or you can negotiate one with them). If you have Grafana running on your servers but you aren't using the code in your own applications then you're generally fine (the GPL is generally recognized as ending where a process ends). And that's the point of the GPL/AGPL, you get the code for free, with the only expectation being that you pass it on if you make any changes.