Bump dompurify and mermaid in /ui

Bumps [dompurify](https://github.com/cure53/DOMPurify) to 3.1.6 and updates ancestor dependency [mermaid](https://github.com/mermaid-js/mermaid). These dependencies need to be updated together.


Updates `dompurify` from 2.4.3 to 3.1.6
- [Release notes](https://github.com/cure53/DOMPurify/releases)
- [Commits](cure53/DOMPurify@2.4.3...3.1.6)

Updates `mermaid` from 10.0.2 to 10.9.1
- [Release notes](https://github.com/mermaid-js/mermaid/releases)
- [Changelog](https://github.com/mermaid-js/mermaid/blob/develop/CHANGELOG.md)
- [Commits](mermaid-js/mermaid@v10.0.2...v10.9.1)

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

Signed-off-by: dependabot[bot] <support@github.com>