Add Dark Mode Visual Style Theme Subclass

[memoarfaa]

This is an improvement to new Dark Mode experimental feature https://github.com/dotnet/winforms/pull/11857 see https://learn.microsoft.com/en-us/windows/win32/controls/theme-subclasses#two-ways-to-use-a-theme-subclass

Fixes https://github.com/dotnet/winforms/issues/11893. Fixes https://github.com/dotnet/winforms/issues/11953.

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