Add DOM Iterable to base tsconfig

[mrkldshv]

Closes #5733.

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[changeset-bot]

🦋 Changeset detected

Latest commit: 172bca5

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

This PR includes changesets to release 1 package

Name	Type
@sveltejs/kit	Patch

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[dummdidumm]

Thank you!