Fix unit control not escaping units

[TimothyBJacobs]

What?

Applies escapeRegExp to unit values when building the regular expression.

Why?

This escapes any units that happen to be regex control characters which prevents the component from crashing due to an invalid regular expression.

Fixes #52210.

Testing Instructions

[stokesman]

This makes sense and works. Thanks for the fix! For my personal itch to get hands-on I tested this in the block editor.

Console paste-able snippet for testing in block settings of a Paragraph block

( ( {
	blockEditor: { InspectorControls },
	components: { PanelBody, __experimentalUnitControl: UnitControl },
	compose: { createHigherOrderComponent },
	element: { createElement: el, Fragment },
	hooks: { addFilter },
} ) => {
	addFilter(
		'editor.BlockEdit',
		'test/unit-control-regexp',
		createHigherOrderComponent( CoreEdit => props => {
			if ( props.name !== 'core/paragraph' ) return el( CoreEdit, props );

			return el( Fragment, null,
				el( InspectorControls, null,
					el( PanelBody, {title: 'Loggy UnitControl'},
						el( UnitControl, {
							onChange: v => console.log( '¡', v, '!' ),
							units: [
								{ value: 'pt', label: 'pt', default: 0 },
								{ value: 'vmax', label: 'vmax', default: 10 },
								{ value: '+', label: '+', default: 10 }
							]
						}),
					)
				),
				el( CoreEdit, props )
			);
		} )
	)
} )( wp );

[TimothyBJacobs]

Thanks for the review @stokesman!