Fix: A potential bug in Win32WindowHelper.cs (#1564)

Modify the code to avoid potential problems(in
'WinUIGallery/Helper/Win32WindowHelper.cs')

## Description
max may have been incorrectly written as min in the code

## Motivation and Context
By analyzing the code, it can be inferred that there might be a problem
here.

## How Has This Been Tested?
Manual test

## Types of changes
<!--- What types of changes does your code introduce? Put an `x` in all
the boxes that apply: -->
- [x] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to change)

WinUIGallery/Helper/Win32WindowHelper.cs

@@ -51,7 +51,7 @@ private nint WndProc(nint hWnd, WindowMessage Msg, nint wParam, nint lParam)
                     if (maxWindowSize != null)
                     {
                         minMaxInfo.ptMaxTrackSize.x = (int)(maxWindowSize.Value.x * scalingFactor);
-                        minMaxInfo.ptMaxTrackSize.y = (int)(minWindowSize.Value.y * scalingFactor);
+                        minMaxInfo.ptMaxTrackSize.y = (int)(maxWindowSize.Value.y * scalingFactor);
                     }
 
                     Marshal.StructureToPtr(minMaxInfo, lParam, true);