Grafana shows warning if metric name does not follow naming convention

[nflaig]

Grafana now shows a warning on panels that use PromQL queries that use functions like rate() which only work on counters but the metric name does not suggest that it is a counter.

We have plenty of metrics like this, e.g. attestation summary on validator monitor dashboard

https://github.com/ChainSafe/lodestar/blob/3076b4cbe34bbe4ebadb005f78f90c256ab31aae/packages/beacon-node/src/metrics/metrics/lodestar.ts#L1009-L1010

To get rid of the warning and more strictly follow Prometheus best practices we would have to update the metric name

-validator_monitor_prev_epoch_attestation_summary
+validator_monitor_prev_epoch_attestation_summary_total

I am not sure if it's worth fixing as it would break existing dashboards but the warnings might also be confusing to users and it would generally be good to follow the recommended naming convention.