Fix incorrect action duration time when rerun the job before executed once (#28364)

Fix #28323
Reason was mentioned here:
https://github.com/go-gitea/gitea/issues/28323#issuecomment-1841867298

### Changes: (maybe breaking)
We can rerun jobs in Gitea, so there will be some problems in
calculating duration time.
In this PR, I use the exist `Started` and `Stopped` column to record the
last run time instead of the total time,
and add a new `PreviousDuration` column to record the previous duration
time.
You can also check the cost time of last run:

![image](2ca39145-2c92-401a-b78b-43164f7ae061)

routers/web/repo/actions/view.go

@@ -279,6 +279,17 @@ func Rerun(ctx *context_module.Context) {
 		return
 	}
 
+	// reset run's start and stop time when it is done
+	if run.Status.IsDone() {
+		run.PreviousDuration = run.Duration()
+		run.Started = 0
+		run.Stopped = 0
+		if err := actions_model.UpdateRun(ctx, run, "started", "stopped", "previous_duration"); err != nil {
+			ctx.Error(http.StatusInternalServerError, err.Error())
+			return
+		}
+	}
+
 	job, jobs := getRunJobs(ctx, runIndex, jobIndex)
 	if ctx.Written() {
 		return