fix: update katex to v0.16.9 and prevent throwing ParseError

[fisheryv]

Update katex to v0.16.9 and prevent throwing ParseError when it encounters an unsupported command or invalid LaTeX.

Actually there are two options if katex encounters an unsupported command：

1. throwOnError = true: Katex will throw a ParseError and we catch the error for further processing;
2. throwOnError = false: Katex will render unsupported commands as text in errorColor.

Here I choose the latter. It expose issues to the front-end so that I can find the error at a glance.

[vercel]

Someone is attempting to deploy a commit to a Personal Account owned by @Innei on Vercel.

@Innei first needs to authorize it.

[Innei]

3Q