Related to #67688

What?

This PR applies the appropriate label to aria-valuetext when the BoxControl component has presets, allowing screen readers to properly announce the preset values.

Why?

The aria-valuenow attribute is used in a range widget to communicate the current value, and the aria-valuetext attribute is used to provide more human-readable text.

The current implementation references the label field, which is always an empty string, so aria-valuetext is effectively non-functional.

How?

From my understanding, the reason the label field is empty is because we do not want to display a visual mark label, so the label field should be left empty. Instead, apply the tooltip text to aria-valuetext as well, so that the text read by screen readers matches the visual tooltip text.

This should match the implementation of the SpacingSizesControl component.

Testing Instructions

• Run npm run storybook:dev
• Access https://localhost:50240/?path=/story/components-boxcontrol--control-with-presets
• Change the value.
• Your screen reader should now read out the actual preset label.
• Confirm the aria-valuetext attribute via your browser developer tools.

Screenshots or screencast