CI/windows: Delete comment for installing vulkan-runtime

Since we're now actually running Vulkan tests on Dozen, the comment
was wrong and we actually want the runtime. The referenced issue
has been fixed anyway.

Acked-by: Daniel Stone <daniels@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/16756>
1 file changed