FIX: Use site contact user + group for Revise... review action (#29271)

Followup 9762e65758

When we added the Revise... option for posts/new topics
in the review queue, which sends a PM to the user, we used
`SystemMessage.create_from_system_user`, which always sends
the PM from the system user. However, this makes it so if the
user replies to the PM, which they are encouraged to do,
no one will see it unless they actively monitor the system inbox.

This commit changes it so `SystemMessage.create` is used,
which uses the `site_contact_username` and `site_contact_group`
site settings as participants in the sent PM. Then, when the
user replies, it will send to that inbox instead.

If `site_contact_username` is blank, the system user is used.

app/models/reviewable_queued_post.rb

@@ -173,7 +173,7 @@ class ReviewableQueuedPost < Reviewable
       original_post: self.payload["raw"],
       site_name: SiteSetting.title,
     }
-    SystemMessage.create_from_system_user(
+    SystemMessage.create(
       self.target_created_by,
       (
         if self.topic.blank?

spec/models/reviewable_queued_post_spec.rb

@@ -126,6 +126,14 @@ RSpec.describe ReviewableQueuedPost, type: :model do
       end
 
       context "with revise_and_reject_post" do
+        fab!(:contact_group) { Fabricate(:group) }
+        fab!(:contact_user) { Fabricate(:user) }
+
+        before do
+          SiteSetting.site_contact_group_name = contact_group.name
+          SiteSetting.site_contact_username = contact_user.username
+        end
+
         it "doesn't create the post the user intended" do
           post_count = Post.public_posts.count
           result = reviewable.perform(moderator, :revise_and_reject_post)
@@ -156,6 +164,8 @@ RSpec.describe ReviewableQueuedPost, type: :model do
             original_post: reviewable.payload["raw"],
             site_name: SiteSetting.title,
           }
+          expect(topic.topic_allowed_users.pluck(:user_id)).to include(contact_user.id)
+          expect(topic.topic_allowed_groups.pluck(:group_id)).to include(contact_group.id)
           expect(topic.first_post.raw.chomp).to eq(
             I18n.t(
               "system_messages.reviewable_queued_post_revise_and_reject.text_body_template",
@@ -175,6 +185,8 @@ RSpec.describe ReviewableQueuedPost, type: :model do
           }
           topic = Topic.where(archetype: Archetype.private_message).last
 
+          expect(topic.topic_allowed_users.pluck(:user_id)).to include(contact_user.id)
+          expect(topic.topic_allowed_groups.pluck(:group_id)).to include(contact_group.id)
           expect(topic.first_post.raw).not_to include("Other...")
           expect(topic.first_post.raw).to include("Boring")
         end

spec/system/reviewables_spec.rb

@@ -130,6 +130,14 @@ describe "Reviewables", type: :system do
   end
 
   context "when performing a review action from the show route" do
+    fab!(:contact_group) { Fabricate(:group) }
+    fab!(:contact_user) { Fabricate(:user) }
+
+    before do
+      SiteSetting.site_contact_group_name = contact_group.name
+      SiteSetting.site_contact_username = contact_user.username
+    end
+
     context "with a ReviewableQueuedPost" do
       fab!(:queued_post_reviewable) { Fabricate(:reviewable_queued_post) }
 
@@ -170,7 +178,11 @@ describe "Reviewables", type: :system do
 
         expect(review_page).to have_reviewable_with_rejected_status(queued_post_reviewable)
         expect(queued_post_reviewable.reload).to be_rejected
-        expect(Topic.where(archetype: Archetype.private_message).last.title).to eq(
+
+        topic = Topic.where(archetype: Archetype.private_message).last
+        expect(topic.topic_allowed_users.pluck(:user_id)).to include(contact_user.id)
+        expect(topic.topic_allowed_groups.pluck(:group_id)).to include(contact_group.id)
+        expect(topic.title).to eq(
           I18n.t(
             "system_messages.reviewable_queued_post_revise_and_reject.subject_template",
             topic_title: queued_post_reviewable.topic.title,