insights: a newly created global insight series will take an indexed recording immediately

Created by: coury-clark

With custom time intervals, when a series is backfilled it now receives historical queries up to the created_at date. However at the same time, it seems to be taking an indexed recording for the same time. This results in a strange looking period of 3 data points after a series is created:

1. one point for the last historical datum
2. one point for the first indexed datum
3. one point for the first snapshot datum

Example series_id on k8s: 22Hei2Y377RmqV4hfQHneRizRvy