fix: correctly validate <svelte:component> with bind:this

[Rich-Harris]

We need to return the instance from bind_this otherwise validate_dynamic_component will get mad. No test because we use the legacy component API in the tests, meaning it doesn't fail in the first place

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[changeset-bot]

🦋 Changeset detected

Latest commit: 7b4b265

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

This PR includes changesets to release 1 package

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svelte	Patch

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[Rich-Harris]

going to merge this, since it's blocking me from running the site locally