Test if listbox has any items before invoking listBox.Items[e.Index] in ListBoxes.cs of the WinformsControlsTests (#13106)

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Fixes #13047


## Proposed changes

- Add a logical judgment before invoking `listBox.Items[e.Index]` in
`ListBox_DrawItem` method in `ListBoxes.cs` of the
`WinformsControlsTest` application to prevent the exception

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## Customer Impact

-  The click event can be done normally on ListBox

## Regression? 

- No

## Risk

- Minimal

<!-- end TELL-MODE -->

## Screenshots <!-- Remove this section if PR does not change UI -->

### Before
Clicking on ListBox Drawmode.OwnerDrawFixed and ListBox
Drawmode.OwnerDrawVariable brings up the exception error window in the
WinformsControlsTest application


![Image](https://github.com/user-attachments/assets/2a83311b-9d98-45a6-b45f-8bd741e084b3)


### After
Everything work well on ListBox 

![AfterChange](https://github.com/user-attachments/assets/b12a2cb7-fca7-4828-ba90-5cf547a4c0a6)



## Test methodology <!-- How did you ensure quality? -->

- Manually tested the application


## Test environment(s) <!-- Remove any that don't apply -->

- .net10.0.0-preview.3.25155.12


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relevant -->

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Author: LeafShi1

src/test/integration/WinformsControlsTest/ListBoxes.cs

@@ -44,8 +44,11 @@ private void ListBox_DrawItem(object sender, DrawItemEventArgs e)
             customBrush = Brushes.Red;
         }
 
-        e.Graphics.DrawString(listBox.Items[e.Index].ToString(),
-            e.Font, customBrush, e.Bounds, StringFormat.GenericDefault);
+        if (listBox.Items.Count > 0)
+        {
+            e.Graphics.DrawString(listBox.Items[e.Index].ToString(),
+                e.Font, customBrush, e.Bounds, StringFormat.GenericDefault);
+        }
 
         e.DrawFocusRectangle();
     }