build(deps): bump mathjax from 3.2.2 to 4.1.0

Bumps [mathjax](https://github.com/mathjax/MathJax) from 3.2.2 to 4.1.0.
- [Release notes](https://github.com/mathjax/MathJax/releases)
- [Commits](https://github.com/mathjax/MathJax/compare/3.2.2...4.1.0)

---
updated-dependencies:
- dependency-name: mathjax
  dependency-version: 4.1.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

package.json

@@ -90,7 +90,7 @@
     "icomoon-free-npm": "^0.0.0",
     "jr-qrcode": "^1.2.1",
     "material-design-icons-iconfont": "^6.7.0",
-    "mathjax": "^3.2.2",
+    "mathjax": "^4.1.0",
     "mousetrap": "^1.6.0",
     "open-dyslexic": "^1.0.3",
     "roboto-fontface": "^0.10.0",