Bump dompurify and @docusaurus/theme-mermaid

Bumps [dompurify](https://github.com/cure53/DOMPurify) to 3.1.6 and updates ancestor dependency [@docusaurus/theme-mermaid](https://github.com/facebook/docusaurus/tree/HEAD/packages/docusaurus-theme-mermaid). These dependencies need to be updated together.


Updates `dompurify` from 2.4.1 to 3.1.6
- [Release notes](https://github.com/cure53/DOMPurify/releases)
- [Commits](cure53/DOMPurify@2.4.1...3.1.6)

Updates `@docusaurus/theme-mermaid` from 2.2.0 to 3.5.2
- [Release notes](https://github.com/facebook/docusaurus/releases)
- [Changelog](https://github.com/facebook/docusaurus/blob/main/CHANGELOG.md)
- [Commits](https://github.com/facebook/docusaurus/commits/v3.5.2/packages/docusaurus-theme-mermaid)

---
updated-dependencies:
- dependency-name: dompurify
  dependency-type: indirect
- dependency-name: "@docusaurus/theme-mermaid"
  dependency-type: direct:production
...

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