ci: Native Windows CI job cleanup
This PR:
- Removes no longer needed workaround for GHA Windows images.
GHA Windows images previously had multiple VC Build Tools installed, which required specifying the VCPKG_PLATFORM_TOOLSET_VERSION explicitly to avoid linker errors. This issue has been resolved as per
https://github.com/actions/runner-images/issues/9701.
- Switches all references to temporary files to relative ones for consistency and readability.