fix: maintain reactivity for properties of deriveds with no deps

[hmnd]

fixes #17111

Oops, thought this fixes - #17352 too but it doesn't yet...

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[changeset-bot]

🦋 Changeset detected

Latest commit: e66b494

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

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svelte	Patch

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Playground

pnpm add https://pkg.pr.new/svelte@17363

[svelte-docs-bot]

Preview: https://svelte-dev-git-preview-svelte-17363-svelte.vercel.app/

[hmnd]

Combining this into #17362 since it's all related