fix(react-router): remove Content-Length header from Single Fetch responses

[rururux]

fixes: #12850
minimal reproduction: https://stackblitz.com/edit/github-pejjugrp?file=app%2Froutes%2Fhome.tsx

While investigating the cause of this issue, I discovered an interesting behavior: removing the Content-Length header from the response results in the application functioning correctly.

Upon further examination, I found the following description in the documentation for Node.js's http module:

Set Content-Length header to limit the response body size.

In fact, when setting a clearly insufficient value such as Content-Length: 6, the response body appears to be affected accordingly.

As described in the issue, this becomes problematic when using response headers intended for redirect responses—such as those generated by authentication libraries—which often do not include a response body.
After considering how best to address this, I concluded that, regardless of whether the response is a redirect, the use of turbo-stream encoding can alter the expected body. Therefore, the most robust solution would be to remove the Content-Length header from all Single Fetch responses, which is what this PR implements.

Additional Notes:
There is a comment on the issue stating that the bug occurred in the development environment but not in production(node20, SSR enabled) . I have yet to determine the reason for this discrepancy.
Nevertheless, since I was able to reliably reproduce and fix the bug, I am submitting this pull request.

[changeset-bot]

🦋 Changeset detected

Latest commit: ab93882

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 11 packages

Name	Type
react-router	Patch
@react-router/architect	Patch
@react-router/cloudflare	Patch
@react-router/dev	Patch
react-router-dom	Patch
@react-router/express	Patch
@react-router/node	Patch
@react-router/serve	Patch
@react-router/fs-routes	Patch
@react-router/remix-routes-option-adapter	Patch
create-react-router	Patch

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[rururux]

Apologies! I accidentally messed up my previous PR #13658 and had to recreate it.
This new PR contains the intended changes.

Thanks in advance for your time and review!

[brophdawg11]

Thanks!

[rururux]

Thank you for merge! 🥳

[github-actions]

🤖 Hello there,

We just published version 7.7.0-pre.0 which includes this pull request. If you'd like to take it for a test run please try it out and let us know what you think!

Thanks!

[github-actions]

🤖 Hello there,

We just published version 7.7.0 which includes this pull request. If you'd like to take it for a test run please try it out and let us know what you think!

Thanks!