Fixes featured hashtag setting page erroring out instead of rejecting invalid tags (#12436)

* Revert "Fix ignoring whole status because of one invalid hashtag (#11621)"

This reverts commit dff46b260b.

* Fix statuses being rejected because of invalid hashtag names

* Add spec for invalid hashtag names in statuses

* Add test for featured tags controller

app/lib/activitypub/activity/create.rb

@@ -157,7 +157,7 @@ class ActivityPub::Activity::Create < ActivityPub::Activity
     return if tag['name'].blank?
 
     Tag.find_or_create_by_names(tag['name']) do |hashtag|
-      @tags << hashtag unless @tags.include?(hashtag)
+      @tags << hashtag unless @tags.include?(hashtag) || !hashtag.valid?
     end
   rescue ActiveRecord::RecordInvalid
     nil