feat: 调整设置，支持导入导出，代码优化

lib/pages/setting/widgets/switch_item.dart

@@ -11,6 +11,7 @@ class SetSwitchItem extends StatefulWidget {
   final bool? defaultVal;
   final Function? callFn;
   final bool? needReboot;
+  final Widget? leading;
 
   const SetSwitchItem({
     this.title,
@@ -19,6 +20,7 @@ class SetSwitchItem extends StatefulWidget {
     this.defaultVal,
     this.callFn,
     this.needReboot,
+    this.leading,
     Key? key,
   }) : super(key: key);
 
@@ -66,6 +68,7 @@ class _SetSwitchItemState extends State<SetSwitchItem> {
       subtitle: widget.subTitle != null
           ? Text(widget.subTitle!, style: subTitleStyle)
           : null,
+      leading: widget.leading,
       trailing: Transform.scale(
         alignment: Alignment.centerRight, // 缩放Switch的大小后保持右侧对齐, 避免右侧空隙过大
         scale: 0.8,