Bump katex from 0.16.10 to 0.16.21

Bumps [katex](https://github.com/KaTeX/KaTeX) from 0.16.10 to 0.16.21.
- [Release notes](https://github.com/KaTeX/KaTeX/releases)
- [Changelog](https://github.com/KaTeX/KaTeX/blob/main/CHANGELOG.md)
- [Commits](KaTeX/KaTeX@v0.16.10...v0.16.21)

---
updated-dependencies:
- dependency-name: katex
  dependency-type: direct:production
...

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

Author: dependabot[bot]

package-lock.json

@@ -35,7 +35,7 @@
     "image-blob-reduce": "^3.0.1",
     "jshashes": "^1.0.8",
     "jwt-decode": "^3.1.2",
-    "katex": "^0.16.10",
+    "katex": "^0.16.21",
     "libav.js": "^4.8.6",
     "libavjs-webcodecs-polyfill": "^0.4.4",
     "pdfjs-dist": "^4.2.67",