[core] AI tagging rule to support more triggers (e.g move, new inbound conversations)

Ideally, we'd want every conversation in our shared inboxes to get tagged so they can be triaged to the appropriate inbox.

• The AI tagging rule doesn't support moves

• Trigger on New Inbound Conversations Only: The AI tagging rule doesn't seem to support this trigger. It only allows triggering on all inbound messages. (worked around this by excluding conversations that are already tagged with one of our conversation category tags)