Description

The <UnitControl> component does not escape the units used to build the firstCharacters regular expression, see

This causes the component to crash with RegExp syntax errors like Nothing to repeat when units are used that contain regex control characters.

There is a escapeRegExp helper that I think could be applied to the first character value.

This looks to be a bug introduced in #39303.

Step-by-step reproduction instructions

1. Use the UnitControl in a block or any React environment with the following code.

<UnitControl
	value={value}
	onChange={onChange}
	units={[
		{
			label: '+',
			value: '+',
		},
		{
			label: '-',
			value: '-',
		},
	]}
/>

Screenshots, screen recording, code snippet

No response

Environment info

• Gutenberg 16.1
• Firefox

Please confirm that you have searched existing issues in the repo.

Yes

Please confirm that you have tested with all plugins deactivated except Gutenberg.

Yes