Manage Vale dependency with ASDF

What does this merge request do and why?

This MR proposes to manage Vale dependency via ASDF, instead of Homebrew. This changes also allow us to pin Vale to a specific version and avoid unexpected breaking change from latest upstream.

Relates to gitlab#419655 (closed)

How to set up and validate locally

1. Verify that vale comes from Homebrew

   ❯ which vale && vale --version
   /opt/homebrew/bin//vale
   vale version 2.28.1

2. Check out to this merge request's branch.
3. Run make platform-update
4. Verify that vale binary now comes from ASDF shim and correct version is set

   ❯ which vale && vale --version
   /Users/tanle/.asdf/shims/vale
   vale version 2.70.1

Impacted categories

The following categories relate to this merge request:

• gdk-reliability - e.g. When a GDK action fails to complete.
• gdk-usability - e.g. Improvements or suggestions around how the GDK functions.
• gdk-performance - e.g. When a GDK action is slow or times out.

Merge request checklist

• This change is backward compatible. If not, please include steps to communicate to our users.
• Tests added for new functionality. If not, please raise an issue to follow-up.
• Documentation added/updated, if needed.
• Announcement added, if change is notable.
• gdk doctor test added, if needed.
• Add the ~highlight label if this MR should be included in the CHANGELOG.md.