Fix for issue when the arrow is clashing with the body border-radius.
There where two ways of fixing it - provide own modifier function for the arrow, or set margin for the arrow.
I've chosen to set margin of the arrow - because in arrow modifier in popper (https://github.com/FezVrasta/popper.js/blob/master/packages/popper/src/modifiers/arrow.js) arrowElementSize includes margins.
Fix for issue when the arrow is clashing with the body border-radius. There where two ways of fixing it - provide own modifier function for the arrow, or set margin for the arrow. I've chosen to set margin of the arrow - because in arrow modifier in popper (https://github.com/FezVrasta/popper.js/blob/master/packages/popper/src/modifiers/arrow.js)
arrowElementSize
includes margins.