Title: A threshold of queries per second that triggers throttling strategy

Description:

The admission control filter rejects requests based on the success rate of previous requests. However, in a low QPS scenario, a small number of request failures will make the request success rate very low, which will trigger the rejection behavior, thereby further reducing the failure rate of subsequent requests. To make matters worse, the filter has a per-worker time window, which means that the QPS carried by each worker is lower.
In fact, in a low QPS scenario, admission control is unnecessary. We can add a QPS threshold configuration and only when the QPS exceeds this threshold, the filter will calculate the failure rate and perform subsequent actions.

cc @tonya11en @mattklein123