insights: add `seriesId` to the timeseries data response in the GraphQL api

Created by: coury-clark

Currently the timeseries object does not contain seriesId. Historically this was because all backend insights seriesId were derived from a hash of the query text, which worked because we could assume all insights were global. As we move into a situation where not all insights are global, it will be necessary to expose this seriesId in the timeseries response.