Increase performance on find_existing_attribute_option_group query

When trying to create alot of options this is really slow

oscarapi/utils/exists.py

@@ -57,9 +57,8 @@ def find_existing_attribute_option_group(name, options):
         AttributeOptionGroup.objects.filter(name=name)
         .annotate(options_count=models.Count("options"))
         .filter(options_count=len(options))
+        .filter(options__option__in=option)
     )
-    for option in options:
-        query = query.filter(options__option=option)
 
     try:
         return query.get()