If the stylesheet does not have a rule that manipulates the font at all
for the menu item, then it should use the one passed into the style
option instead.

Task-number: QTBUG-65034
Change-Id: I6cae3fad3cc22d5ab2b984e4a58b14303bcd6d03
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
Reviewed-by: Gabriel de Dietrich <gabriel.dedietrich@qt.io>