Fix light theme script injection bug

scratch/port_streak_clean.py

@@ -99,9 +99,8 @@ def port_html():
     }
   })();
 </script>
-</body>
     """
-    html = html.replace("</body>", light_theme_script)
+    html += light_theme_script
 
     with open(dest_path, 'w', encoding='utf-8') as f:
         f.write(html)