Description

When only one option is passed to the units prop in UnitControl component the onChange always returns px.

Ex on pattern that will return px:

const [ value, setValue ] = useState( '10%' );

<UnitControl
	value={ value }
	unit="%"
	units={ [ { value: '%', label: '%' } ] }
	onChange={ setValue }
/>

How has this been tested?

Testet with both multiple and single option in units prop.

Screenshots

Before

After

Types of changes

Bug fix

Checklist:

• My code is tested.
• My code follows the WordPress code style.
• My code follows the accessibility standards.
• I've tested my changes with keyboard and screen readers.
• My code has proper inline documentation.
• I've included developer documentation if appropriate.
• I've updated all React Native files affected by any refactorings/renamings in this PR (please manually search all *.native.js files for terms that need renaming or removal).