Sanitize docs content to prevent XSS

[gtsp233]

Fix for Cross-Site Scripting (XSS) Vulnerability

Hi, I've found a Cross-Site Scripting (XSS) vulnerability in the package @icedesign/richtext-renderer.

Vulnerability Details:

• Severity: High/Critical
• Description: There's a risk of malicious content is passed to docs

POC(Proof of Concept)

import React, { useEffect } from "react";
import { Documentation } from "@blueprintjs/docs-theme";

const App = () => {
  return (
    <Documentation
      docs={{
        nav: [],
        pages: {
          test: {
            reference: "foo",
            route: "foo",
            sourcePath: "foo",
            title: "foo",
            contents: ["<img src='' onerror=alert(1)>"],
          },
        },
        docs: {
          pages: [],
        },
      }}
      defaultPageId="foo"
    />
  );
};

export default App;

Changes proposed in this pull request:

Sanitize the HTML before rendering it using dangerouslySetInnerHtml

I've already fixed this issue, and have submitted a pull request with the necessary changes. Please review and merge my pull request to resolve this vulnerability. Thanks!

Reviewers should focus on:

Screenshot

[palantirtech]

Thanks for your interest in palantir/blueprint, @gtsp233! Before we can accept your pull request, you need to sign our contributor license agreement - just visit https://cla.palantir.com/ and follow the instructions. Once you sign, I'll automatically update this pull request.

[adidahiya]

This is a developer build tool that is not exposed directly to end users (only developers building documentation sites). Why does this sanitization need to happen in the Blueprint package? If it's a concern for a downstream consumer, then perhaps @icedesign/richtext-renderer should do the sanitization?