fix(a11y): Unified search headings

[Pytal]

• For [BITV] 9.1.3.1a/9.1 - The page lacks an "h1" heading, and the existing "h2" heading, "Groups," does not accurately describe the content of the page and therefore cannot serve as the main heading for the page. (1) #41829

Summary

Before	After

• Only a single h1 page heading should be present on the page

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)

[Pytal]

/backport ad8ae7b to stable28