fix: Bubble charts a11y issue

[georgylobko]

Description

AWSUI-61878
Added ARIA label attribute for the cartesian bubble chart

Related links, issue #, if available: n/a

How has this been tested?

Review checklist

The following items are to be evaluated by the author(s) and the reviewer(s).

Correctness

• Changes include appropriate documentation updates.
• Changes are backward-compatible if not indicated, see CONTRIBUTING.md.
• Changes do not include unsupported browser features, see CONTRIBUTING.md.
• Changes were manually tested for accessibility, see accessibility guidelines.

Security

• If the code handles URLs: all URLs are validated through the checkSafeUrl function.

Testing

• Changes are covered with new/existing unit tests?
• Changes are covered with new/existing integration tests?

---

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[pan-kot]

why is typecast needed here?

[georgylobko]

Because we are casting to readonly type here. Made it slightly differently to align with a similar code for the tooltip

[pan-kot]

The same code is used in the tooltip - should we make a matchSizeAxis() helper?

[georgylobko]

Sounds good. Addressed

[pan-kot]

nit: would it make sense to make size and formatter extraction in the util?

export function getMatchedSizeAxisProps(sizeAxis, point) {
  const series = point.series;
  const matched = sizeAxis?.find((a) => a.id === getBubbleSeriesSizeAxis(series)) ?? sizeAxis?.[0];
  if (!matched) {
    return null;
  }
  return { size: point.options.z ?? null, formatter: getFormatter(matched) };
}

[pan-kot]

or maybe just return the formatted size?

[pan-kot]

export function getFormattedSize(sizeAxis, point) {
  const series = point.series;
  const matched = sizeAxis?.find((a) => a.id === getBubbleSeriesSizeAxis(series)) ?? sizeAxis?.[0];
  if (!matched) {
    return null;
  }
  const size = point.options.z ?? null;
  const formatter = getFormatter(matched);
  return formatter(size);
}

[georgylobko]

I'd say we would barely benefit from it, because we need the matchedSizeAxis title in the tooltip, while we don't need it in the getPointAccessibleDescription, so I would keep it as is for now. No strong opinion here, but if we need to reuse or extend it at some point in future, we can always do this

[pan-kot]

sizeAxis is not optional as its argument type suggests, so no need to use optional chaining here

[georgylobko]

addressed