Apply suggestion from @luelista

I took this from the original implementation, but I think this actually isn't necessary? At least when I tested it, it works fine without, and I don't see how it would do anything, as the importmap is a script and not a style.

src/pretix/base/templatetags/vite.py

@@ -242,7 +242,6 @@ def vite_importmap(context):
     if request:
         csp_hash = calculate_csp_hash(json_string)
         add_to_response_csp_via_request(request, {
-            'style-src': [csp_hash],
             'script-src': [csp_hash],
         })