Only return status and has_unread_feedback if remix

Author: jamiebenstead

app/views/api/lessons/student_index.json.jbuilder

@@ -3,7 +3,10 @@
 json.array!(@lessons_with_users_and_remixes) do |lesson_with_user, remix|
   lesson, user = lesson_with_user
   json.partial! 'lesson', lesson: lesson, user: user
-  json.status(remix&.school_project&.status)
-  json.has_unread_feedback(remix&.school_project&.unread_feedback?)
   json.remix_identifier(remix.identifier) if remix.present?
+  if remix.present?
+    json.status(remix.school_project&.status)
+    json.has_unread_feedback(remix.school_project&.unread_feedback?)
+    json.remix_identifier(remix.identifier)
+  end
 end