[EuiDataGrid][AXE-CORE]: Column re-order flyout has double-nested drag handle buttons

[1Copenut]

Description

The EuiDataGrid uses our EuiDraggable to re-order columns in a header control (see attached screenshot). These drag handles are throwing axe errors because there's a second div[role="button"] wrapping it.

There is a second issue with the drag handles not having an accessible label. @1Copenut is handling that. Tracking issue is #5911.

Guidance

• https://dequeuniversity.com/rules/axe/4.4/aria-hidden-focus
• https://www.w3.org/WAI/WCAG21/Understanding/name-role-value.html

Screenshot