Update ruby default version to 3.2.5
What does this MR do and why?
Followup to the ruby upgrade to version 3.2.5 gitlab-com/gl-infra/production#18519 (closed), this MR is to update the default ruby version in CI to match the one that we upgraded to.
MR acceptance checklist
Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.