Revert "samples/UnitConverter.Wpf: Use double example values"

This reverts commit 896f765.

Author: angularsen

Samples/UnitConverter.Wpf/UnitConverter.Wpf/MainWindowDesignVM.cs

@@ -30,8 +30,8 @@ public MainWindowDesignVm()
 
         public string FromHeader { get; } = "Value [cm]";
         public string ToHeader { get; } = "Result [dm]";
-        public QuantityValue FromValue { get; set; } = 14.5;
-        public QuantityValue ToValue { get; } = 1.45;
+        public QuantityValue FromValue { get; set; } = 14.5m;
+        public QuantityValue ToValue { get; } = 1.45m;
 
         public ICommand SwapCommand { get; } = new RoutedCommand();