Open submission upload file link in a new tab.

opentech/apply/stream_forms/templates/stream_forms/includes/file_field.html

-<a class="link link--download" href="{{ file.url }}">
+<a class="link link--download" href="{{ file.url }}" target="_blank">
     <div>
         <svg><use xlink:href="#file"></use></svg>
         <span>{{ file.filename }}</span>