@Herrmann you would either need to overwrite the module where the HTML is coming from, or you can overwrite the CSS for the class so you don’t have to remove it from the HTML.
Are you trying to change the style of the hs-menu-children-wrapper class?
If so, you can use the child.css file in the child theme (if you’re website is built with one) or add it to the Site Header HTML in your Website settings.
You could then redefine the CSS definitions for the class.
If you can share a website page link, I’m happy to inspect the code to see where the change needs to be made.