fix: port over props that were set prior to initialization

[dummdidumm]

...and then delete the property descriptor that shadows the prototype descriptor fixes #9487

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[changeset-bot]

🦋 Changeset detected

Latest commit: 8ab911c

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

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[RichardValerosoUniverse]

...and then delete the property descriptor that shadows the prototype descriptor fixes #9487

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

Yjdju