You are sending request to their servers, they will save at least your IP request there.
There is no need to do that. You can just download the font and use it in your own server.
No offence, but to me, this sounds a little paranoid, doesn’t it? I mean, we talking here about font style. I am not sure is it possible to be 100% safe over the internet if you use all of his resources.
It can easily change an IP address, restarting router. Maybe I am naive, but I really don't see a serious problem here.
..
You just need this code:
<div class="dropdown">
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.5.2/css/bootstrap.min.css" integrity="sha384-JcKb8q3iqJ61gNV9KGb8thSsNjpSL0n8PARn9HuZOnIxN0hoP+VmmDGMN5t9UJ0Z" crossorigin="anonymous">
<script src="https://code.jquery.com/jquery-3.5.1.slim.min.js" integrity="sha384-DfXdz2htPH0lsSSs5nCTpuj/zy4C+OGpamoFVy38MVBnE+IbbVYUew+OrCXaRkfj" crossorigin="anonymous"></script>
<script src="https://getbootstrap.com/docs/4.5/dist/js/bootstrap.bundle.min.js" integrity="sha384-LtrjvnR4Twt/qOuYxE721u19sVFLVSA4hf/rRt6PrZTmiPltdZcI7q7PXQBYTKyf" crossorigin="anonymous">
Now you here linking to
bootstrapcdn.com jquery.com and
getbootstrap.com. here is also a problem, because this way they can find out your IP address and whatever they were doing with this information. Especially when it comes to dynamic address, by the way, who knows who had that address before us and where he was.