feat(Reboot): increase reboot count down time (#7335)

* doc: 更新倒计时时长为 4 分钟

* doc: 更新时长

Author: ArgoZhang

src/BootstrapBlazor.Server/Components/Components/RebootCountDown.razor

@@ -1,3 +1,3 @@
-<div class="bb-reboot-clock">
-    <FlipClock ViewMode="FlipClockViewMode.CountDown" ShowHour="false" StartValue="TimeSpan.FromSeconds(140)"></FlipClock>
+<div class="bb-reboot-clock">
+    <FlipClock ViewMode="FlipClockViewMode.CountDown" ShowHour="false" StartValue="TimeSpan.FromSeconds(240)"></FlipClock>
 </div>