well thats gonna be some custom coding... what you can do is use the console element inspector to see what css covers that and then add the custom css to your admin theme section and put display:none; for that css and it should go away. The problem is that you have to check it becaue that css could be used by other items and you might just clear the whole page, or things you dont want to.
So try that, if that does not work, i will see if i can find the html for you. However every time you update you will need to add the change again if we do it this way.