[Fix-8624][UI-Next][V1.0.0-Alpha] Rectify the issue to display the timing form when clicking the timing button in the process definition page. (#8704)

* fix this issue

* fix this issue

dolphinscheduler-ui-next/src/views/projects/workflow/definition/components/timing-modal.tsx

@@ -187,6 +187,8 @@ export default defineComponent({
     watch(
       () => props.row,
       () => {
+        if (!props.row.crontab) return
+
         timingState.timingForm.startEndTime = [
           new Date(props.row.startTime),
           new Date(props.row.endTime)