Follow up to the cgroup PR #40519

[Feng Wang (chemwolf6922)]

Summary of the Pull Request

This PR serves as a follow up to comments in #40519

1. Remove the redundant string encoding conversion in std::format.
2. Add user warning when cgroup v1 is enabled and point the user to the correct .wslconfig setting.

PR Checklist

• Closes: Link to issue #xxx
• Communication: I've discussed this with core contributors already. If work hasn't been agreed, this work might be rejected
• Tests: Added/updated if needed and all pass
• Localization: All end user facing strings can be localized
• Dev docs: Added/updated if needed
• Documentation updated: If checked, please file a pull request on our docs repo and link it here: #xxx

Detailed Description of the Pull Request / Additional comments

Validation Steps Performed

[Copilot]

Pull request overview

This PR follows up on feedback from #40519 by simplifying a test helper’s std::format usage around wide-string inputs and by adding a user-facing warning when cgroup v1 is enabled in a configuration that indicates per-distribution cgroup isolation.

Changes:

• Remove a redundant wide→narrow conversion in LxssWriteWslDistroConfig() by relying on the repo’s std::formatter<const wchar_t*, char> specialization.
• Emit a user warning when cgroup v1 is selected while a per-distro cgroup path is present (indicating isolation is in effect).
• Add the corresponding en-US localized string for the new warning message.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
test/windows/Common.cpp	Simplifies path formatting by formatting LPCWSTR directly into a narrow std::format string.
src/linux/init/config.cpp	Adds an EMIT_USER_WARNING when cgroup v1 is requested alongside per-distro isolation context.
localization/strings/en-US/Resources.resw	Adds a new localized resource string for the cgroup v1 incompatibility warning.

[Copilot]

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

[Copilot]

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated no new comments.

[Copilot]

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated no new comments.