Drag & Drop: provide global 'isDragging' state, expose via render prop param

[thompsongl]

Currently, EuiDraggable knows about its current dragging state (isDragging) and EuiDroppable knows about whether it is currently a valid drop target (isDraggingOver).

We need an extra data point—likely on EuiDragDropContextContext—to provide higher-level awareness that something is currently dragging, exclusive of direct relationships.

Relatedly, we'll need a mechanism by which to expose this and other context data, most likely via render prop parameters, similar to react-beautiful-dnd's snapshot

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👋 Hey there. This issue hasn't had any activity for 180 days. We'll automatically close it if that trend continues for another week. If you feel this issue is still valid and needs attention please let us know with a comment.

[github-actions]

👋 Hey there. This issue hasn't had any activity for 180 days. We'll automatically close it if that trend continues for another week. If you feel this issue is still valid and needs attention please let us know with a comment.

[github-actions]

❌ We're automatically closing this issue due to lack of activity. Please comment if you feel this was done in error.