TriangleMouseFilter: also check optional position has value
If firstEnter is true, only item is set, and interceptedHoverEnterPosition still has no value until there is another QEvent::HoverEnter event. Amends 1e8a8d6e CCBUG: 473432
If firstEnter is true, only item is set, and interceptedHoverEnterPosition still has no value until there is another QEvent::HoverEnter event. Amends 1e8a8d6e CCBUG: 473432
mentioned in commit 88780c84