Fix flakey test in logger test (#24883)

Fix #24882

The goroutines are all asynchronized. So it needs a little "sleep" to
make sure the writer's goroutine has been paused before sending messages
to it.

Co-authored-by: Giteabot <[email protected]>

Author: wxiaoguang

modules/log/logger_test.go

@@ -94,6 +94,7 @@ func TestLoggerPause(t *testing.T) {
 	logger.AddWriters(w1)
 
 	GetManager().PauseAll()
+	time.Sleep(50 * time.Millisecond)
 
 	logger.Info("info-level")
 	time.Sleep(100 * time.Millisecond)