FIX: If you don't have permission to onebox a post, just show the link instead of crashing out

lib/oneboxer/discourse_local_onebox.rb

@@ -21,7 +21,7 @@ module Oneboxer
         user = User.where(username_lower: route[:username].downcase).first
         return nil unless user
 
-        Guardian.new.ensure_can_see!(user)
+        return @url unless Guardian.new.can_see?(user)
 
         args.merge! avatar: PrettyText.avatar_img(user.username, 'tiny'), username: user.username
         args[:bio] = user.bio_cooked if user.bio_cooked.present?
@@ -33,7 +33,7 @@ module Oneboxer
           post = Post.where(topic_id: route[:topic_id], post_number: route[:post_number].to_i).first
           return nil unless post
 
-          Guardian.new.ensure_can_see!(post)
+          return @url unless Guardian.new.can_see?(post)
 
           topic = post.topic
           slug = Slug.for(topic.title)
@@ -52,7 +52,8 @@ module Oneboxer
           topic = Topic.where(id: route[:topic_id].to_i).includes(:user).first
           return nil unless topic
 
-          Guardian.new.ensure_can_see!(topic)
+          return @url unless Guardian.new.can_see?(topic)
+
           post = topic.posts.first
 
           posters = topic.posters_summary.map do |p|