What to do with a student coming to class in revealing clothing, to the degree that it disrupts the teaching environment?

Unlike my answer here, your problem does not seem to be about the clothing, but rather the disruption. Assuming the student is not breaking the university dress code, then it is not her who is disrupting the teaching environment, but other students.

You have not provided examples of how the response of the other students is disrupting the teaching environment, but the solution really doesn't matter that the cause of the disruptive behavior is the appearance of another individual. Simply remind students that the disruptive behavior (talking, hooting, leering, taking photos) is disruptive and will not be tolerate. If the students continue to be disruptive, throw them out of class.

The best thing you can do is the escalate the problem to your superiors, which you already did. Note that in disputes like this (when there is a bad and a worse choice, like you being accused of being either a harasser or a perv) the important thing is to let know your employer that there is a problem. That may be very important for your defense if you are forced to intervene if she starts to behave even more provocatively. So make sure that you have indisputable proof that you notified your superiors of a problem early.

Perhaps I would go even further. If you live in a liberal EU country, you may have dedicated university services taking care of sexual harassment, gender equality and similar. If you feel uncomfortable with her behavior, turn the tables on her, and go to the sexual harassment counselor and notify them. Gender equality goes both ways! If you (or your male students) would come into class in spandex swimming trunks, exposing the outline of your genitals, I believe the women in the audience would rightly feel this is inappropriate and constitutes harassment. So go to the counselor and report the situation. The counselor will have perhaps more knowledge how to tackle this or even she (it is probably a woman) will take the matter into her own hands.

As with your superiors, this may protect you if the girl starts acting even more unreasonably and you will have to intervene on short notice.

Ignore everyone here and ask your higher-ups what to do. Then do it.

And get at least some of the responses in writing so that you can point back to them.

I believe this is the only correct and safe way to proceed. End of story.