update xcopy msbuild to 17.12.0

[riarenas]

https://github.com/dotnet/dnceng/issues/4443

Updates the xcopy msbuild to a version that works with the latest sdks.

I ran a validation build of these changes through arcade-validation here: https://dev.azure.com/dnceng/internal/_build/results?buildId=2581359&view=results

To double check:

• [ ] The right tests are in and the right validation has happened. Guidance: https://github.com/dotnet/arcade/blob/main/Documentation/Validation.md

[riarenas]

/backport to release/9.0

[github-actions[bot]]

Started backporting to release/9.0: https://github.com/dotnet/arcade/actions/runs/11976945707