Fix detect-tests CI job

What does this MR do and why?

The detect-tests job is failing in https://gitlab.com/gitlab-renovate-forks/gitlab/-/jobs/6326977771 because ruby:3.1-slim doesn't come with gcc and make, which is needed to build native extensions. activesupport depends on i18n, which depends on racc. racc has a native extension.

This is needed because yesterday the i18n gem added racc as a runtime dependency in 1.14.3: https://github.com/ruby-i18n/i18n/pull/680

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• This MR is backporting a bug fix, documentation update, or spec fix, previously merged in the default branch.
• The MR that fixed the bug on the default branch has been deployed to GitLab.com (not applicable for documentation or spec changes).
• This MR has a severity label assigned (if applicable).
• Set the milestone of the merge request to match the target backport branch version.
• This MR has been approved by a maintainer (only one approval is required).
• Ensure the e2e:package-and-test-ee job has either succeeded or been approved by a Software Engineer in Test.

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