Improve on eval script on web browsing tasks; Add one setup example

desktop_env/evaluators/metrics/utils.py

@@ -625,6 +625,9 @@ def are_lists_equal(list1, list2, comparison_func):
 
 
 def compare_urls(url1, url2):
+    if url1 is None or url2 is None:
+        return url1 == url2
+
     def normalize_url(url):
         # Parse the URL
         parsed_url = urlparse(url)