Remove unused _isParsing var

Author: Rosuavio

Microsoft.Toolkit.Uwp.SampleApp/SamplePages/CanvasPathGeometry/CanvasPathGeometryPage.xaml.cs

@@ -95,7 +95,6 @@ public sealed partial class CanvasPathGeometryPage : Page
         private Color _strokeColor;
         private Color _fillColor;
         private bool _selectionChanged = false;
-        private bool _isParsing = false;
 
         private CanvasGeometry _errorGeometry;
         private GeometryStreamReader _reader;
@@ -172,9 +171,7 @@ public CanvasPathGeometryPage()
         private void ParseData()
         {
             _data = InputData.Text;
-            _isParsing = true;
             RenderCanvas.Invalidate();
-            _isParsing = false;
         }
 
         private void OnCanvasDraw(CanvasControl sender, CanvasDrawEventArgs args)