Show Backpressure Status

In order to enhance the monitoring capabilities, it is essential to provide real-time visibility into the status of operators and the edges connecting them. Within our backend system, we have implemented a mechanism known as "Back Pressure." This mechanism ensures that if an operator receives an excessive amount of data that surpasses its processing capacity, it will signal its upstream components to pause data transmission temporarily. This status needs to be reflected on the frontend to let users better understand and also let our developers better debug the execution behavior.