[EuiCollapsibleNavBeta] Consider adding aria-hidden="true" to the icon button for screen reader UX #7353

[Kukki8]

Summary

This PR provides:

• An added aria-hidden={buttonIsInteractive ? 'true' : 'false'} tag to the accordion_trigger.tsx file, as advised in the issue description.

This PR doesn't contain:

• Changes in UI

Implementation

QA

Remove or strikethrough items that do not apply to your PR.

General checklist

• Browser QA
  • Checked in both light and dark modes
  • Checked in mobile
  • Checked in Chrome, Safari, Edge, and Firefox
  • Checked for accessibility including keyboard-only and screenreader modes
• Docs site QA
  • Added documentation
  • Props have proper autodocs (using @default if default values are missing) and playground toggles
  • Checked Code Sandbox works for any docs examples
• Code quality checklist
  • Added or updated jest and cypress tests
  • Updated visual regression tests
• Release checklist
  • A changelog entry exists and is marked appropriately.
  • If applicable, added the breaking change issue label (and filled out the breaking change checklist)
• Designer checklist
  • If applicable, file an issue to update EUI's Figma library with any corresponding UI changes. (This is an internal repo, if you are external to Elastic, ask a maintainer to submit this request)

[github-actions]

👋 Since this is a community submitted pull request, a Buildkite build has not been started automatically. Would an Elastic organization member please verify the contents of this pull request and kick off a build manually?