Follow up from https://github.com/sourcegraph/sourcegraph/issues/45745

We will want to support the ability to export data as if from a user context. This data should include both data available on the chart (series_points / series_points_snapshots) as well as any truncated data for the series. Exporting in CSV is probably simple enough, and I think we do that elsewhere in the product.

/cc @Joelkw @felixfbecker @vovakulikov