Enhancements to last_activity_at in the User Management API

This update enhances the durability of the last_activity_at field in the Copilot API to further ensure reliable activity tracking by improving the resilience and scaling of the pipeline. No breaking changes to the API schema have been introduced.

Please note:

• The last_activity_at field offers insight into usage of the features outlined in our public documentation.
• The refresh period for activity metrics remains unchanged: activity may take up to 30 minutes to appear in the API.