Revisit padding in test suite report table

What does this MR do and why?

This revisits the padding in the test suite report table to be mobile-first instead of desktop-first.

• TODO: Add mobile-first gl-sm-pr-2 util to GitLab UI: gitlab-ui!3055 (merged).

Screenshots or screen recordings

Without right padding	With right padding

How to set up and validate locally

1. Run yarn to install the dev build of @gitlab/ui which contains the necessary CSS utils.
2. Set up unit test reports in a project: https://docs.gitlab.com/ee/ci/testing/unit_test_reports.html#how-to-set-it-up.
3. Run a pipeline.
4. When the pipeline completes, navigate to it, activate the Tests tab and click on a job.

MR acceptance checklist

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

• I have evaluated the MR acceptance checklist for this MR.