insights: Update groupBy for repo-scoped series
Created by: CristinaBirkel
Closes https://github.com/sourcegraph/sourcegraph/issues/38872
Description
There's a separate codepath for updating repo-scoped series, and the groupBy value was not getting piped through. This PR fixes that.
Test plan
Try updating a repo-scoped series and make sure that the group_by
field is updated in the insight_series
table correctly, and that the right value is returned in the API response as well.