fix: statistic countdown not trigger "finish" event (#1731)

* fix: fix the "finish" event of statistic countdown

* fix: update the fix of "finish" event of statistic countdown

* fix: update the fix of "finish" event of statistic countdown

Author: hebingchang

Diff for: components/statistic/Countdown.jsx

@@ -48,6 +48,7 @@ export default {
       if (this.countdownId) return;
       this.countdownId = window.setInterval(() => {
         this.$refs.statistic.$forceUpdate();
+        this.syncTimer();
       }, REFRESH_INTERVAL);
     },