LogRemoveMember
data class LogRemoveMember(val convoId: String, val message: SystemMessageDataRemoveMember, val rev: String)
NOTE: This is under active development and should be considered unstable while this note is here. Event indicating a member was removed from a group convo. The member who was removed gets a logLeaveConvo (to leave the convo) but not a logRemoveMember (because they already left, so can't see the system message).