EuiTablePagination: Adds data-test-subj to the EuiContextMenuItem

[ffknob]

Summary

Closes #2762

Added data-test-subj to the EuiContextMenuItem in EuiTablePagination

Checklist

• Check against all themes for compatibility in both light and dark modes
• Checked in mobile
• Checked in IE11 and Firefox
• Props have proper autodocs
• Added documentation examples
• Added or updated jest tests
• Checked for breaking changes and labeled appropriately
• Checked for accessibility including keyboard-only and screenreader modes
• A changelog entry exists and is marked appropriately

[kibanamachine]

Since this is a community submitted pull request, a Jenkins build has not been kicked off automatically. Can an Elastic organization member please verify the contents of this patch and then kick off a build manually?

[chandlerprall]

Thanks for submitting this!

We'd like data-test-subj to specify the number of rows represented by each option, and in a way the developer doesn't have to explicitly provide the prop as the only data here is an array of numbers and there isn't a great way to give individual test props. For our components which are more internal (it's unlikely someone would use EuiTablePagination directly), it's common to hard-code the data-test-subj instead of accepting it as a prop.

The attribute here would be something like

data-test-subj={`tablePagination-${itemsPerPageOption}-rows`}

[chandlerprall]

Needs an entry to CHANGELOG.md, but otherwise looks good.

[chandlerprall]

jenkins test this

[chandlerprall]

Changes LGTM; pulled and tested locally