FIX: Use destroy_all instead of delete_all for shared drafts

Rails has an odd behavior for calling .delete_all on a has_many relation - the
default behavior is to nullify the foreign key fields instead of actually
'DELETE'ing the records.

Additionally, publishing a shared draft topic creates a PostRevision that the
NotifyPostRevision job picks up which is then promptly deleted.

Use destroy_all when cleaning up the revisions and have the NotifyPostRevision
job tolerate deleted PostRevision records.

This takes a small performance hit (several SQL DELETEs instead of just one)
but shouldn't be too much of an issue (high cardinalities range from 30-100).

app/jobs/regular/notify_post_revision.rb

@@ -6,7 +6,7 @@ module Jobs
       raise Discourse::InvalidParameters.new(:user_ids) unless args[:user_ids]
 
       post_revision = PostRevision.find_by(id: args[:post_revision_id])
-      raise Discourse::InvalidParameters.new(:post_revision_id) unless post_revision
+      return if post_revision.nil?
 
       ActiveRecord::Base.transaction do
         User.where(id: args[:user_ids]).find_each do |user|

lib/topic_publisher.rb

@@ -36,7 +36,7 @@ class TopicPublisher
       op = @topic.first_post
 
       if op.present?
-        op.revisions.delete_all
+        op.revisions.destroy_all
 
         op.update_columns(
           version: 1,