Add support for exactOptionalPropertyTypes to @react-types/button.

[quisido]

First implementation iteration of #8717

✅ 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:

Consumers of @react-types/button should be able to explicitly pass undefined as a property value and achieve the same behavior as not providing the property at all.

🧢 Your Project:

private