Go through and fix or intentionally ignore grafana/dashboard-linter rules we break

The rules are described in https://github.com/grafana/dashboard-linter/blob/main/docs/index.md#rules, and our errors are seen in test run failures such as [here](https://github.com/jupyterhub/grafana-dashboards/actions/runs/8743609565/job/23994544209).

We have a lot of linting errors currently.