Preserve order of supplied zsh completion candidates

ArgumentParser version: main
Swift version:
swift-driver version: 1.120.5 Apple Swift version 6.1 (swiftlang-6.1.0.110.21 clang-1700.0.13.3)
Target: arm64-apple-macosx15.0

Checklist

• If possible, I've reproduced the issue using the main branch of this package
• I've searched for existing GitHub issues

Steps to Reproduce

Use zsh completions for some parameter that generates completion candidates via custom, list, or shellCommand that returns candidates that are not sorted.

Expected behavior

Candidates preserve order.

Actual behavior

Candidates are sorted.