Fix datasource variable usage in the dashboard

[kinduff]

@colega Thanks a lot for your contribution.

I'm wondering, what's the advantage of having this field declared?

[colega]

Oh, sorry, the commit message wasn't added as PR description 🤦

It was:

Some "dashboard" fields were set to null, which broke the queries on the import.

This field is present in most of the panes, which work properly, but where it's set to null, Grafana sets the datasource to the example Grafana datasource when dashboard is imported, and the Prometheus query is lost forever.

Setting "dashboard" to the one selected during the import makes everything work just fine.

[kinduff]

Perfect, thanks a lot for your contribution. Merging this.

[kinduff]

@all-contributors please add @colega for content

[allcontributors[bot]]

@kinduff

I've put up a pull request to add @colega! :tada: