No, they aren't. Sexual harassment includes unwanted advances, and attractiveness to the specific target has some role in whether an advances is unwanted or not, but sexual harassment includes lots of behaviors that are not unwanted (by the person to whom they are directed) sexual advances (an advance desired by the person to whom it is directed may easily be, or be part of, sexual harassment of third parties when conducted within a workplace context) or even sexual advances at all, and merely being attractive itself doesn't make all sexual advances wanted, in any case.