So I just got a warning from Google search console that I’ve got a new mobile usability issue, which is where it tells me that my viewport is not set.
Is there a way to set the viewport somehow within Webflow’s code? Or should I just not worry about this warning?
Thanks! 
The viewport is a short tag that is included in the head of your HTML document that tells the browser how the page should be rendered. Read more
webflow auto specify a viewport using the meta viewport tag (browser - right click → view page source)
<meta name="viewport" content="width=device-width, initial-scale=1">
Google docs ( console Mobile usability report):
Google docs - viewport tag
Your viewport with horizontally scroll?
If so, try to fix this issue.