[ML] Fixes empty table header cell and duplicate ID accessibility issues

[peteharverson]

Summary

Fixes a couple of accessibility issues on table components in the ML and Transforms plugins.

• Fixes [ML] (Accessibility) - Machine Learning - Anomaly Detection / Job Management - Table Headings #52376 table header cells should not be empty. Added screen reader content for each of the empty table headers.
• Fixes [ML] (Accessibility) Anomaly Detection/Anomaly Explorer - Multiple elements same ID #52381 popovers in anomalies table action cells had duplicate IDs. Removed the redundant id attribute from the actions popover.

Checklist

• This was checked for cross-browser compatibility, including a check against IE11
• Any text added follows EUI's writing guidelines, uses sentence case text and includes i18n support
• This was checked for keyboard-only and screenreader accessibility

For maintainers

• This includes a feature addition or change that requires a release note and was labeled appropriately

[elasticmachine]

Pinging @elastic/ml-ui (:ml)

[kibanamachine]

💚 Build Succeeded

• continuous-integration/kibana-ci/pull-request
• Commit: 21ac2df

History

• 💔 Build #20579 failed 3509430

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@elasticmachine merge upstream

[alvarezmelissa87]

LGTM ⚡️

[jgowdyelastic]

LGTM