add scrolling to about package

mih_ui/lib/mih_package_components/mih_single_child_scroll.dart

@@ -2,9 +2,11 @@ import 'package:flutter/material.dart';
 
 class MihSingleChildScroll extends StatefulWidget {
   final Widget child;
+  final bool? scrollbarOn;
   const MihSingleChildScroll({
     super.key,
     required this.child,
+    this.scrollbarOn,
   });
 
   @override
@@ -18,7 +20,8 @@ class _MihSingleChildScrollState extends State<MihSingleChildScroll> {
       bottom: false,
       minimum: EdgeInsets.only(bottom: 5),
       child: ScrollConfiguration(
-        behavior: ScrollConfiguration.of(context).copyWith(scrollbars: false),
+        behavior: ScrollConfiguration.of(context)
+            .copyWith(scrollbars: widget.scrollbarOn ?? false),
         child: SingleChildScrollView(
           child: widget.child,
         ),