[macOS] Update Ruby installer script due to #13050

[erik-bershel]

Description

Replacing #13051 for macOS due to how our repo processes work and some issues with the initial PR.

Related issue:

#13050

Check list

• Related issue / work item is attached
• Tests are written (if applicable)
• Documentation is updated (if applicable)
• Changes are tested and related VM images are successfully generated

[Copilot]

Pull Request Overview

Updates the macOS Ruby installer script to adjust how Ruby toolcache versions are resolved and downloaded, replacing suffix-based asset selection with a dynamic release asset resolution.

• Introduces resolve_github_release_asset_url for fetching version-specific archives
• Removes ruby_suffix logic and simplifies setup of toolcache directory
• Minor messaging and structural adjustments (variable initialization moved earlier)

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