Check if icon exists before copying

UWPHook/GamesWindow.xaml.cs

@@ -541,9 +541,16 @@ namespace UWPHook
 
             string dest_file = String.Join(String.Empty, icons_path, app.Aumid + Path.GetFileName(icon_to_copy));
             try
+            {
+                if (File.Exists(icon_to_copy))
                 {
                     File.Copy(icon_to_copy, dest_file, true);
                 }
+                else
+                {
+                    dest_file = app.Icon;
+                }
+            }
             catch (System.IO.IOException e)
             {
                 Log.Warning(e, "Could not copy icon " + app.Icon);