Docker Cli legacy build deprecated on windows with no replacement available

[nrcventura]

Description

When attempting to build windows docker images from windows github runners, the docker cli reports an error that the legacy builder is deprecated.

     DEPRECATED: The legacy builder is deprecated and will be removed in a future release.
                 Install the buildx component to build images with BuildKit:
                 https://docs.docker.com/go/buildx/

The problem is that buildx and buildkit do not work well on windows, and any support for them is still experimental.

Either this warning is being incorrectly applied when attempting to build windows containers, or this deprecation is happening before windows containers can be supported by the newer build systems.

See open-telemetry/opentelemetry-dotnet-instrumentation#4876 for an attempt to enable buildx and buildkit on a github windows runner and a link to an example job that failed with the legacy builder deprecation message.

Reproduce

1. Setup a github actions job to run on a windows runner
2. Use the docker cli to build a windows container.
3. Sometimes it will successfully, and other times it fails with the deprecation message.

Expected behavior

Either the windows docker containers should continue to built using the legacy builder, or the newer build system needs to fully support windows containers.

docker version

N/A

docker info

N/A

Additional Info

See https://github.com/actions/runner-images/blob/main/images/windows/Windows2025-Readme.md for the information about which docker tools (and their versions) are installed on windows runners.