Build: Re-enable spider check for CodePen links

Follows-up 3ef1eb4. I reached out to CodePen Support and they've
allowed the User-Agent used by hydra-link-checker.

Author: Krinkle

build/hydra-config.json

@@ -4,15 +4,13 @@
     "2024-06: npmjs.com responds HTTP 429 Too Many Requests too easily",
     "2024-07: element.io and gitter.im chat rooms render fine but oddly use HTTP 404",
     "2025-01: github.com responds HTTP 429 Too Many Requests for the bulk of trivial links. We can probably keep a few other GitHub links.",
-    "2025-03: codepen.io (via Cloudflare) blocks hydra-link-checker with HTTP 403",
     ""
   ],
   "exclude_scheme_prefixes": [
     "https://twitter.com/",
     "https://app.element.io/",
     "https://app.gitter.im/",
     "https://www.npmjs.com/package/",
-    "https://codepen.io/",
     "https://github.com/qunitjs/qunit/issues/",
     "https://github.com/qunitjs/qunit/pull/",
     "https://github.com/qunitjs/qunit/blob/main/docs/_posts/"

docs/_posts/2022-02-15-qunit-2-18-0.md

@@ -12,7 +12,7 @@ Introduce partial object comparison, support TypeScript in watch mode, add globa
 
 ### Added
 
-* Assert: New [`assert.propContains()`](% link api/assert/propContains.md %}) for partial object comparison. (Izel Nakri) [#1668](https://github.com/qunitjs/qunit/pull/1668)
+* Assert: New [`assert.propContains()`]({% link api/assert/propContains.md %}) for partial object comparison. (Izel Nakri) [#1668](https://github.com/qunitjs/qunit/pull/1668)
 * Core: Add `QUnit.hooks` to globally add beforeEach and afterEach. (Timo Tijhof) [#1475](https://github.com/qunitjs/qunit/issues/1475)
 * CLI: Add support for watching `.ts` files when TypeScript is used. (Timo Tijhof) [#1669](https://github.com/qunitjs/qunit/issues/1669)
 * CLI: Add support for watching `.json`, `.cjs`, and `.mjs` files. [#1676](https://github.com/qunitjs/qunit/pull/1676)