Building ML.NET on Windows has a new dependency

**System Information (please complete the following information):**
- OS & Version: Win11 23H2
- ML.NET Version: main as of 3/11/2024
- .NET Version: N/A

**Describe the bug**
When building ML.NET I now hit:
```
error MSB8040: Spectre-mitigated libraries are required for this project. Install them from the Visual Studio installer (Individual components tab) for any toolsets and architectures being used. Learn more: https://aka.ms/Ofhn4c
```

I was able to fix this by manually installing: "Libs for Spectre" as mentioned here: https://learn.microsoft.com/en-us/cpp/build/reference/qspectre?view=msvc-160