Right now, deleting a capture agent will delete the roles associated
with a capture agent from all existing users, regardless of the roles
having been assigned to that user before the agent was created or not.
This may lead to weird situations where user loose access when capture
agents are temporarily deleted but again added later on.
The issue described here also leads to all users losing all group membership when a capture agent is deleted.
Cherry picked this into r/6.x as aedf9d5fd691fd87edf110f7dd400509438d44a6, should get into 6.5.