[MM-62864] Bump katex to 0.16.21 (#30095)

webapp/channels/package.json

@@ -45,7 +45,7 @@
     "html-to-react": "1.6.0",
     "inobounce": "0.2.1",
     "ipaddr.js": "2.1.0",
-    "katex": "0.16.10",
+    "katex": "0.16.21",
     "localforage": "1.10.0",
     "localforage-observable": "2.1.1",
     "lodash": "4.17.21",