Bump highlight.js from 9.18.5 to 10.4.1 in /site-ui

Bumps [highlight.js](https://github.com/highlightjs/highlight.js) from 9.18.5 to 10.4.1.
- [Release notes](https://github.com/highlightjs/highlight.js/releases)
- [Changelog](https://github.com/highlightjs/highlight.js/blob/main/CHANGES.md)
- [Commits](highlightjs/highlight.js@9.18.5...10.4.1)

---
updated-dependencies:
- dependency-name: highlight.js
  dependency-version: 10.4.1
  dependency-type: direct:development
...

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Author: dependabot[bot]

site-ui/package-lock.json

@@ -39,7 +39,7 @@
     "gulp-uglify": "~3.0",
     "gulp-vinyl-zip": "~2.2",
     "handlebars": "~4.7.8",
-    "highlight.js": "~9.18.5",
+    "highlight.js": "~10.4.1",
     "jquery": "~3.5.1",
     "js-yaml": "~3.14",
     "mark.js": "~8.11",