MM-32882: Add an unread badge/marker to the Main Menu icon and the ‘Plugin Marketplace’ Menu Item (#16992)

model/websocket_message.go

@@ -73,6 +73,7 @@ const (
 	WEBSOCKET_EVENT_THREAD_UPDATED                           = "thread_updated"
 	WEBSOCKET_EVENT_THREAD_FOLLOW_CHANGED                    = "thread_follow_changed"
 	WEBSOCKET_EVENT_THREAD_READ_CHANGED                      = "thread_read_changed"
+	WEBSOCKET_FIRST_ADMIN_VISIT_MARKETPLACE_STATUS_RECEIVED  = "first_admin_visit_marketplace_status_received"
 )
 
 type WebSocketMessage interface {