fix: better ownership mutation validation

[dummdidumm]

Fixes #10649

• widen ownership when getContext/getAllContexts is called
• widen ownership when assigning one proxy to another
• skip first 4 stack trace entries and bail if first after that is not a module, hinting at a mutation encapsulated in a .svelte.js file

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• Ideally, include a test that fails without this PR but passes with it.

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[changeset-bot]

🦋 Changeset detected

Latest commit: 0c781e3

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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[trueadm]

LGTM!