Ernesto, I changing the component to Ceph Dashboard for now. cephadm doesn't really care which Grafana Version we're deploying, as long as the version is compatible to the Dashboard. Feel free to change it back, as soon as you come to a conclusion.
*** This bug has been marked as a duplicate of bug 1996090 ***
Sunil, I'm afraid that might be the case. Our Grafana is not the vanilla one, but a custom version with a couple of plugins + dashboards embedded.