Previously, we did similar work in SERVER-125516, but it turns out that the search task executor stats don't emit in FTDC because of the bug reported in SERVER-126178. We want these metrics in FTDC since we'll need them to diagnose bugs related to the search task executors. As such, this ticket emits the search task executor stats in server status rather than connPoolStats. Once SERVER-126178 is completed, we can move these stats back to connPoolStats since that's a better solution here.