Bump dompurify from 2.4.4 to 2.5.4 in /src/headless

Bumps [dompurify](https://github.com/cure53/DOMPurify) from 2.4.4 to 2.5.4.
- [Release notes](https://github.com/cure53/DOMPurify/releases)
- [Commits](cure53/DOMPurify@2.4.4...2.5.4)

---
updated-dependencies:
- dependency-name: dompurify
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>