fix: fetch body

[PeytonHanel]

fix: Provided fetch function accepts the same object types in the body as the native fetch function

See #9420

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[changeset-bot]

🦋 Changeset detected

Latest commit: c788235

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

This PR includes changesets to release 1 package

Name	Type
@sveltejs/kit	Patch

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[PeytonHanel]

I'm not sure why it says no changeset found, I generated one and it's in the files changed section.

[Conduitry]

The changeset needs to be created from the root of the repo. It looks like you initialized another changesets installation within the packages/kit directory.

[Rich-Harris]

For posterity: it looks like the reason this is okay is that we just don't serialize fetch responses in the case where request.body exists and isn't a string:

kit/packages/kit/src/runtime/server/page/load_data.js

Line 234 in 4e10640

if (!body || typeof body === 'string') {

[Rich-Harris]

thank you!