[dragDrop] On strict movement when dropping outside cdkDropList

#### Feature Description

There is one problem with this, because of some action after dragging on cdkDragDrop.

1. Drag the item.
2. Go through the drop zone.
3. Drop outside the drop zone.

In the case of dragDrop in angular / cdk, when dropping outside the drop zone, the item moves to the last drop zone where the item was entered.


In the dragula, apart from entering the drop zone, it returns to its original state when dropped outside the drop zone.


Therefore, it would be nice to provide an strict method of returning to angular / cdk dragdrop as an option.

Please let me know if there is a way around this.

thank you

Start by reproducing the reported drag sequence with Angular CDK drag-and-drop: enter a cdkDropList, then drop outside it. Compare the result with the expected return to the original position and review the existing drag-drop behavior and discussion for an agreed API. Done means the strict behavior is available as an option and is covered by tests.

Written by the indexing model from the issue text.