Add scroll bar to mih

mih_ui/lib/mih_packages/calculator/package_tools/currency_exchange_rate.dart

@@ -290,6 +290,7 @@ class _CurrencyExchangeRateState extends State<CurrencyExchangeRate> {
     return Consumer<MihCalculatorProvider>(
       builder: (context, calculatorProvider, child) {
         return MihSingleChildScroll(
+          scrollbarOn: true,
           child: Padding(
             padding:
                 MzansiInnovationHub.of(context)!.theme.screenType == "desktop"

mih_ui/lib/mih_packages/calculator/package_tools/simple_calc.dart

@@ -94,6 +94,7 @@ class _SimpleCalcState extends State<SimpleCalc> {
       }
     }
     return MihSingleChildScroll(
+      scrollbarOn: true,
       child: Column(
         mainAxisAlignment: MainAxisAlignment.start,
         mainAxisSize: MainAxisSize.min,

mih_ui/lib/mih_packages/calculator/package_tools/tip_calc.dart

@@ -259,6 +259,7 @@ class _TipCalcState extends State<TipCalc> {
 
   Widget getBody(double width) {
     return MihSingleChildScroll(
+      scrollbarOn: true,
       child: Padding(
         padding: MzansiInnovationHub.of(context)!.theme.screenType == "desktop"
             ? EdgeInsets.symmetric(horizontal: width * 0.2)