Investigate duplicates in clickhouse ci_finished_builds

During the Ingest ci_builds for gitlab.com to ClickHouse (#421204 - closed) we discovered that we for some reason duplicate some ci builds information in ClickHouse.

We should investigate it and potential fixes.

More in the Slack thread: https://gitlab.slack.com/archives/C04D13QHUH1/p1697128960335969?thread_ts=1697100646.680059&cid=C04D13QHUH1