Remove source-build prebuilt detection from fsharp

See https://github.com/dotnet/source-build/issues/5034 for details

- [x] Remove `eng/SourceBuildPrebuiltBaseline.xml` if one exists
- [x] Remove all source build intermediate dependencies in `Version.Details.xml`

This should only be done on branches that do not flow into a 9.0 SDK. If the branch flows into a 9.0 SDK, these changes must wait.