fix: include missing utils file when publishing

[eltigerchino]

#13844 moved a utility function to its own file but forgot to add that file to the files array in the package.json so it's not included when published.

This PR adds that file to the package.json

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🦋 Changeset detected

Latest commit: bca6c8d

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

This PR includes changesets to release 1 package

Name	Type
@sveltejs/adapter-cloudflare	Patch

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