NumberControl: Increment and Decrement buttons aren't operable with keyboard

[afercia]

Description

I'm not sure what is the reasoning behind making the NumberControl Increment and Decrement buttons not operable with a keyboard. That seems intentional as:

• These buttons have a tabIndex="-1" attribute so they're not focusable.
• They are hidden from assistive technology by the means of aria-hidden="true".
• However, they do have an aria-label attribute.

Regardless of the inconsistent implementation, there is no apparent reason why these buttons should not be usable with a keyboard.

Screenshot of an instance of NumberControl Increment and Decrement buttons:

Step-by-step reproduction instructions

• Use Twenty Twenty Four as active theme
• Go to Site Editor > Templates > Blog Home
• Use the Tab key to move focus to the 'Posts per page' field.
• Press the Tab key again.
• Observe the Increment and Decrement buttons get skipped bevause they're made not focusable.

Screenshots, screen recording, code snippet

No response

Environment info

No response

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

[afercia]

For reference: the custom spin controls were adder here, with a comment mentioning them as progressive enhancement and hidden from screen readers.

#45333

The buttons are a progressive enhancement hidden from screen readers.

The progressive enhancement concept is totally fine but there's no reason to make them not operable with a keyboard.