Properly handle multipart file uploads in the dev server

[matthewp]

Changes

• When converting the body for a Response, concat the raw bytes rather than converting to a string.
• Closes Multipart/form-data file encoding issue #4737

Testing

• Test added

Docs

N/A, bug fix

[changeset-bot]

🦋 Changeset detected

Latest commit: 8e89b47

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

This PR includes changesets to release 16 packages

Name	Type
astro	Patch
@e2e/astro-component	Patch
@e2e/error-cyclic	Patch
@e2e/error-react-spectrum	Patch
@e2e/error-sass	Patch
@e2e/errors	Patch
@e2e/hydration-race	Patch
@e2e/lit-component	Patch
@e2e/preact-component	Patch
@e2e/react-component	Patch
@e2e/solid-component	Patch
@e2e/solid-recurse	Patch
@e2e/svelte-component	Patch
@e2e/e2e-tailwindcss	Patch
@e2e/ts-resolution	Patch
@e2e/third-party-astro	Patch

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