Fix: circular dependency in @internationalized/date

[luixo]

Closes a relevant issue

The copy and copyDateTime seem to be unused and not exported outside of the package.
They also break Vercel deployments of the projects that use @internationalized/date for some reason (probably connected with the heroui issue), that's why I made the fix.

✅ Pull Request Checklist:

• Included link to corresponding React Spectrum GitHub Issue.
• Added/updated unit tests and storybook for this change (for new code or code which already has tests).
• Filled out test instructions.
• Updated documentation (if it already exists for this component).
• Looked at the Accessibility Practices for this feature - Aria Practices

📝 Test Instructions:

All existing tests should pass.

[snowystinger]

Thanks for the pr, you'll need to sign the CLA before we can review it https://react-spectrum.adobe.com/contribute.html#contributor-license-agreement. Thanks!

[luixo]

Thanks for the pr, you'll need to sign the CLA before we can review it

Done

[snowystinger]

confirmed, they aren't being used elsewhere
I'm not sure why we have these, @devongovett do you recall? it looks like it wasn't used in the PR it was introduced in either 0e528a5#diff-d2fb7ef0cb40b4a7bc8b2eb2beddd89028c1426dd3c3a704c1d8894ec13f2294