Enable highlighting of a selected table row in Winforms (#3293)

Ensures that a Winforms table still renders the selected row when it doesn't have focus.

Author: JDarsley

changes/3269.bugfix.rst

@@ -0,0 +1 @@
+Enable persisted highlighting of a selected table row in Winforms.

winforms/src/toga_winforms/widgets/table.py

@@ -52,6 +52,7 @@ def create(self):
         self.native.VirtualMode = True
         self.native.Columns.AddRange(dataColumn)
         self.native.SmallImageList = WinForms.ImageList()
+        self.native.HideSelection = False
 
         self.native.ItemSelectionChanged += WeakrefCallable(
             self.winforms_item_selection_changed