[Sprint/PinkPanther](fix): Refactored logic for moderation queue to not query Cassandra for post count.
Summary
Closes #1031 (closed)
Currently on the production stack, if you moderate an older group, you will likely have posts still counted in your moderation queue, showing "4 posts unapproved", when you click, there is none.
Testing
This should be tested on a subdomain connected to production. If you do not have access to such a group ask me, and I will arrange that.