feat(cdk/drag-drop): allow drag to be canceled after dragged over list

[andrewseguin]

Feature Description

Items actively dragged from one list to another, but without releasing the drag, cannot be canceled. The list changes immediately and the user cannot undo the action. This issue tracks the request to enable an API that lets dragging be canceled, e.g. by undo'ing the list changes (or not change the lists at all) if the item is not dropped onto a drop container

Use Case

No response