Revert "Fix CORS (Cross-origin resource sharing) errors (#1952)"

[karreiro]

WHY are these changes introduced?

The CdnAssets middleware, introduced by #1952, was throttling asset requests.

WHAT is this pull request doing?

This PR reverts #1952 to quick fix this issue. On a future PR, it's probably a good idea to use the ShopifyCLI:: ThreadPool to serve assets in the CdnAssets. Still, for now, this PR undo the changes.

How to test your changes?

• Run shopify theme serve
• Add many assets that rely on //cdn.shopify.com URLs
• Notice in the browser console how requests are affected

Before this revert:

After this revert:

Post-release steps

None.

Update checklist

• I've added a CHANGELOG entry for this PR (if the change is public-facing)
• I've considered possible cross-platform impacts (Mac, Linux, Windows).
• I've left the version number as is (we'll handle incrementing this when releasing).
• I've included any post-release steps in the section above.

[pinguluk]

Yep, localhost wasn't loading at all and it was stuck on the .js files. Installed shopify-cli-2.10.1 version and it's working fine again

[joshuaiz]

Thank you for this fix 💯

[albertoziveri]

Still not working. Rendering a section in Localhost is still blocked by version 2.10.1
Explained very well here: #1466