Remove duplicate entries that did not make it to ITEM_SENT

[jsutantio]

User Story
As a product manager and ReportStream team member, I would like my dashboard's data source to be the most accurate and reliable so that the resultant calculations and dashboards are less prone to error.

Description
This is a continuation of #16067, which swapped the datasource to the ITEM_SENT event.

The task is to remove the duplicative results that were caused by resubmissions or filtered out reports, which were accounted for in the ITEM_ROUTED event.

Considerations
Prior notes

• Tried to match Properties.reportId from REPORT_SENT with those of ITEM_ROUTED in the aug16explosion table.
• I could not find any matches. This may be because the the reportId is generated for each step? I’ll need to next track based on parentReportId or trackingId (most promising field).
• This means that I’ll need to go back into Power Query to display the trackingId column on all the existing data (lots of data).
• Try for just the aug16explosion table first.
• See if there exists a lookup function to delete rows with duplicative trackingId’s but keeps the one row that has REPORT_SENT… but then I’ll still need the observational data in ITEM_ROUTED.

Acceptance Criteria

• Remove duplicates from current date to as far back as possible (theoretically Aug 8 when more advanced metadata was being recorded in Azure)
• Document changes in the documentation PowerPoint
• Publish updated OKR Metrics Dashboard