Bump development Ruby version to 3.2.2

What does this MR do and why?

All our CI pipelines already pass for Ruby 3.2, so let's bump to Ruby 3.2.2 to flush out any other issues that might arise.

We also need to copy the GDK's .ruby-version into the gitlab/ directory. This follows the change made in !132816 (merged).

The build-gdk-image job attempts to install GitLab with a given GDK version. If the Ruby version is updated in the gitlab/ directory, the GDK pre-flight checker will detect that the GDK Ruby version is inconsistent.

To avoid build failures that result from this, use the GDK .ruby-versions as the canonical file by copying it into the gitlab directory since that's what's actually installed.

This will help avoid causing broken builds whenever .tool-versions change.