fix(EuiBetaBadge): add accessible name to span with role=button for better A11y

[alexwizp]

Summary

This PR fixes a problem introduced in #9100 , where a role="button" was added to a EuiBetaBadge -> <span> element.

Unfortunately, that change prevents us from updating Kibana, as the configured AXE Core accessibility checks flag it as a violation:

[aria-command-name]: Ensure every ARIA button, link, and menuitem has an accessible name  
Impact: serious  
Help: https://dequeuniversity.com/rules/axe/4.10/aria-command-name?application=axeAPI  
Elements:  
  - <span tabindex="0" role="button" class="euiBetaBadge css-rbgvzw-euiBetaBadge-hollow-m-baseline">  
  - <span tabindex="0" role="button" class="euiBetaBadge css-rbgvzw-euiBetaBadge-hollow-m-baseline">  

Fix
This PR adds the required aria-label attribute to provide an accessible name for the button element, resolving the AXE violation.

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• 💚 Build #1639 succeeded dacf37a

[elasticmachine]

💚 Build Succeeded

• Buildkite Build
• Commit: 24431e1

History

• 💔 Build #4986 failed dacf37a