reuse existing attribute value query in serializer

Author: drusepth

app/models/serializers/content_serializer.rb

@@ -113,7 +113,9 @@ def initialize(content)
   def value_for(attribute_field, content)
     case attribute_field.field_type
     when 'link'
-      page_links = attribute_field.attribute_values.find_by(entity_type: content.class.name, entity_id: content.id)
+      page_links = self.attribute_values.detect do |value|
+        value.entity_type == content.class.name && value.entity_id == content.id && value.attribute_field_id == attribute_field.id
+      end
       if page_links.nil?
         # Fall back on old relation value
         # We're technically doing a double lookup here (by converting response