[activation] Shared AI training for same tag across AI tagging rules

Situation: when I want to create an AI tagging rule for multiple inboxes, all using the same tag (e.g., VIP), I have to train the AI, by reviewing message samples, separately for each rule, even though it's the same tag.

Request: Streamline the process by allowing the training to be done only once if the tag description is consistent across the different AI tagging rules and inboxes.

Impact: Reduce the time it takes to configure the rules (effort and also having enough training message samples). More AI tagging adoption.