use dataset thumbnail if available

[qqmyers]

New Contributors

Welcome! New contributors should at least glance at CONTRIBUTING.md, especially the section on pull requests where we encourage you to reach out to other developers before you start coding. Also, please note that we measure code coverage and prefer you write unit tests. Pull requests can still be reviewed without tests or completion of the checklist outlined below. Thanks!

Related Issues

• connects to #5641 (edited by @djbrooke)

Pull Request Checklist

• [ ] Unit tests completed
• [ ] Integration tests: None
• [ ] Deployment requirements, SQL updates, Solr updates, etc.: None
• [ ] Documentation completed
• [ ] Merged latest from "develop" branch and resolved conflicts