Active repo list should include repos with at least 2 pushers?

The active repositories [list](https://autodesk.github.io/hubble/demo-data/repository-activity-detailed.tsv) includes repositories with only 1 pusher. While many important projects are individual efforts, I wonder if this useful information in Hubble. Insisting on projects with at least 2 pushers in Hubble will very often reduce noise and allow Hubble consumers to focus on projects
where more effective collaboration is a true goal.

Start with the active repositories list linked in the issue and trace how that data is generated. Determine where the pusher count is available and apply the proposed two-pusher threshold there; done means repositories with fewer than two pushers no longer appear in the active list.

Written by the indexing model from the issue text.