tests: Remove 'out' event assertions
tests: Remove 'out' event assertions

`out` is only emitted when `_lastDropTarget` is truthy.
jimf/dragula,looker/dragula,luckylooke/dragon,sherbrow/dragula,rlugojr/dragula,romainbessugesmeusy/dragula,bevacqua/dragula,linearza/dragula,sherbrow/dragula,linearza/dragula,jaw4ik/dragula,jaw4ik/dragula,luckylooke/dragon,jimf/dragula,rwillbrown/dragula,rwillbrown/dragula,rlugojr/dragula,bevacqua/dragula,romainbessugesmeusy/dragula,looker/dragula