[VO] Infinite loop when adding a Windows Form to an sdk project

When adding a WinForms Form, an infinite loop occurs in Visual Studio 2026 with an  SDK-style project.

[XSharpTestsSdk.zip](https://github.com/user-attachments/files/30831442/XSharpTestsSdk.zip)

<img width="290" height="991" alt="Image" src="https://github.com/user-attachments/assets/5861f0cc-8663-492c-853f-1a21a4102de9" />

