Sign wslcsdk.dll in the release pipeline

[OneBlue]

Summary of the Pull Request

This change adds logic to sign wslcsdk.dll

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

Updates the release build stage pipeline to ensure wslcsdk.dll is included in the ESRP code-signing pass, aligning the pipeline output with the SDK/NuGet packaging inputs that consume bin\<arch>\Release\wslcsdk.dll.

Changes:

• Add the wslcsdk CMake target to the set of release pipeline build targets.
• Add wslcsdk.dll to the code-signing/copy-to-staging pattern list used by the ESRP signing step.