Grafana dashboard warm/non-warm container metrics not working

## Environment details:

* Kubernetes deployment
* Docker version 19.03.6, Ubuntu 18.04.4 LTS 4.15.0-1065-aws

## Steps to reproduce the issue:

1. deploy OW on Kubernetes using https://github.com/apache/openwhisk-deploy-kube.git
2. connect to dashboard at https://apihost/monitoring/dashboards
3. check out Action Performance Metrics

## Provide the expected results and outputs:

```
Warm/non-warm container starts show the correct numbers.
```

## Provide the actual results and outputs:

```
Warm/non-warm container starts figures show random lines, and constantly changing:
```

## Additional information you deem important:
* seems this statement is not evaluated correctly https://github.com/apache/openwhisk/blob/master/core/monitoring/user-events/compose/grafana/dashboards/openwhisk_events.json#L1559