fix(@react-aria/select): avoid empty option in hidden select markup

[sonsu-lee]

Closes #8085

✅ 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:

1. Run yarn jest packages/@react-aria/select — two new tests should pass:

• should include a non-empty placeholder option for native select markup
• should submit an empty string when no value is selected

2. In a Select story with no default value, inspect the hidden <select> and verify the first <option> is <option value="" label="\u00A0"> (no longer empty)

🧢 Your Project:

• Personal