Bump katex in /extensions/ql-vscode in the npm_and_yarn group

Bumps the npm_and_yarn group in /extensions/ql-vscode with 1 update: [katex](https://github.com/KaTeX/KaTeX).


Updates `katex` from 0.16.18 to 0.16.21
- [Release notes](https://github.com/KaTeX/KaTeX/releases)
- [Changelog](https://github.com/KaTeX/KaTeX/blob/main/CHANGELOG.md)
- [Commits](https://github.com/KaTeX/KaTeX/compare/v0.16.18...v0.16.21)

---
updated-dependencies:
- dependency-name: katex
  dependency-type: indirect
  dependency-group: npm_and_yarn
...

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

extensions/ql-vscode/package-lock.json

@@ -17246,9 +17246,9 @@
       }
     },
     "node_modules/katex": {
-      "version": "0.16.18",
-      "resolved": "https://registry.npmjs.org/katex/-/katex-0.16.18.tgz",
-      "integrity": "sha512-LRuk0rPdXrecAFwQucYjMiIs0JFefk6N1q/04mlw14aVIVgxq1FO0MA9RiIIGVaKOB5GIP5GH4aBBNraZERmaQ==",
+      "version": "0.16.21",
+      "resolved": "https://registry.npmjs.org/katex/-/katex-0.16.21.tgz",
+      "integrity": "sha512-XvqR7FgOHtWupfMiigNzmh+MgUVmDGU2kXZm899ZkPfcuoPuFxyHmXsgATDpFZDAXCI8tvinaVcDo8PIIJSo4A==",
       "dev": true,
       "funding": [
         "https://opencollective.com/katex",