Fix spacing between pagination and next group

What does this MR do and why?

Fixes the spacing issue between pagination and next group.

Related #425523 (closed)

Screenshots or screen recordings

Before	After

How to set up and validate locally

1. Enable feature flag: echo "Feature.enable(:vulnerability_report_grouping)" | rails c
2. Fork https://gitlab.com/gitlab-examples/security/security-reports/
3. Create a pipeline against the default branch
4. Go to Secure > Vulnerability Report
5. Use the Group By Button
6. Check the spacing between pagination and next group

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.