If mouse hovering over an undo modal, don't hide it until the mouse leaves

[joeowenca]

If your mouse is hovering over an undo modal, the undo modal should stay as long as the mouse continues to hover it.

Once the 10000ms timer is up, the undo modal will stay while the mouse is hovering.

Once the mouse leaves, there can be an additional 1000ms delay to allow time for it to go or unintentional mouse-off movements.

[joeowenca]

Blocked as I am struggling to retain the elements getBoundingClientRect()'s position when the component re-renders. On mount, the 'elementPosition' state is set to 'undefined'. So therefore, each time the component re-renders, the position is lost.

[joeowenca]

re-opened as this only works if there is one undo item. Please refer to above comment for further issues.