Subgroup & Member events Group Webhook - Add audit tracking information

Release notes

Problem to solve

For customers that are security and compliance-focused, who takes an action is just as important as the action itself. It would be helpful to know which user created, updated, or deleted a subgroup/group member in webhook events.

Proposal

Add an attribute to the subgroup/group member webhook event that specifies the user that took the action that triggered the event.