fix: don't blank css on migration error

[paoloricciuti]

Svelte 5 rewrite

This

<script>
	export let error = true;
</script>

<div>
	{$$props}
</div>

<style lang="postcss">
	div{
		color: red;
	}
</style>

was erroneusly migrated to

<!-- @migration-task Error while migrating Svelte code: $$props is used together with named props in a way that cannot be automatically migrated. -->
<script>
	export let error = true;
</script>

<div>
	{$$props}
</div>

<style lang="postcss">/*$$__STYLE_CONTENT__$$*/</style>

Please note that the Svelte codebase is currently being rewritten for Svelte 5. Changes should target Svelte 5, which lives on the default branch (main).

If your PR concerns Svelte 4 (including updates to svelte.dev.docs), please ensure the base branch is svelte-4 and not main.

Before submitting the PR, please make sure you do the following

• It's really useful if your PR references an issue where it is discussed ahead of time. In many cases, features are absent for a reason. For large changes, please create an RFC: https://github.com/sveltejs/rfcs
• Prefix your PR title with feat:, fix:, chore:, or docs:.
• This message body should clearly illustrate what problems it solves.
• Ideally, include a test that fails without this PR but passes with it.

Tests and linting

• Run the tests with pnpm test and lint the project with pnpm lint

[changeset-bot]

🦋 Changeset detected

Latest commit: 710c3a6

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

This PR includes changesets to release 1 package

Name	Type
svelte	Patch

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