activity: align closer to upstream

app/lib/activitypub/activity/create.rb

@@ -59,7 +59,6 @@ class ActivityPub::Activity::Create < ActivityPub::Activity
       attach_tags(@status)
       attach_mentions(@status)
       attach_counts(@status)
-      attach_quote(@status)
     end
 
     resolve_thread(@status)
@@ -483,10 +482,6 @@ class ActivityPub::Activity::Create < ActivityPub::Activity
     mime_type.present? && !MediaAttachment.supported_mime_types.include?(mime_type)
   end
 
-  def blurhash_valid_chars?(blurhash)
-    /^[\w#$%*+-.:;=?@\[\]^{|}~]+$/.match?(blurhash)
-  end
-
   def skip_download?
     return @skip_download if defined?(@skip_download)