Only count contributors with active public items for type count

[jwalgran]

Overview

We recently updated the contributors filter dropdown to only contain
contributors that have active, public list items. In this commit we fix the
contributor type counts by applying the same filter criteria before counting.

Connects #1001

Testing Instructions

• Run ./scripts/resetdb
• Browse http://localhost:6543/, open the contributor types dropdown and verify that "Auditor" has a count of "[1]"
• Register a new account with type "Auditor," confirm it, and log in.
• Browse http://localhost:6543/, open the contributor types dropdown and verify that "Auditor" still has a count of "[1]"
• Browse http://localhost:6543/contribute and upload one-bad-one-good.csv.zip
• Process the list through the first 2 steps
  • ./scripts/manage batch_process --list-id 16 --action parse
  • ./scripts/manage batch_process --list-id 16 --action geocode
• Browse http://localhost:6543/, open the contributor types dropdown and verify that "Auditor" still has a count of "[1]"
• Process the list through the final step
  • ./scripts/manage batch_process --list-id 16 --action match
• Browse http://localhost:6543/, open the contributor types dropdown and verify that "Auditor" now has a count of "[2]"

Checklist

• fixup! commits have been squashed
• CI passes after rebase
• CHANGELOG.md updated with summary of features or fixes, following Keep a Changelog guidelines

[TaiWilkin]

Looks good, and worked as expected

[jwalgran]

Thanks for the review.