Bump dompurify from 2.2.3 to 2.2.6

Bumps [dompurify](https://github.com/cure53/DOMPurify) from 2.2.3 to 2.2.6.
- [Release notes](https://github.com/cure53/DOMPurify/releases)
- [Commits](https://github.com/cure53/DOMPurify/compare/2.2.3...2.2.6

)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>
Signed-off-by: npmbuildbot-nextcloud[bot] <npmbuildbot-nextcloud[bot]@users.noreply.github.com>