build(deps): bump sanitize-html and @edx/paragon

Removes [sanitize-html](https://github.com/apostrophecms/sanitize-html). It's no longer used after updating ancestor dependency [@edx/paragon](https://github.com/openedx/paragon). These dependencies need to be updated together.


Removes `sanitize-html`

Updates `@edx/paragon` from 3.4.8 to 21.5.6
- [Release notes](https://github.com/openedx/paragon/releases)
- [Changelog](https://github.com/openedx/paragon/blob/release-23.x/CHANGELOG.md)
- [Commits](openedx/paragon@v3.4.8...v21.5.6)

---
updated-dependencies:
- dependency-name: sanitize-html
  dependency-version: 
  dependency-type: indirect
- dependency-name: "@edx/paragon"
  dependency-version: 21.5.6
  dependency-type: direct:production
...

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

Author: dependabot[bot]