disapprovals: don't dmail uploaders about disapprovals.

Remove sending dmail notifications to uploaders when an upload is
disapproved. These messages are usually confusing and frustrating to
uploaders. They don't know who is sending them and they usually feel
insulted when they get negative messages from anonymous users.

test/unit/post_disapproval_test.rb

@@ -67,33 +67,6 @@ class PostDisapprovalTest < ActiveSupport::TestCase
         end
       end
 
-      context "when sending dmails" do
-        setup do
-          @uploaders = FactoryBot.create_list(:user, 2, created_at: 2.weeks.ago)
-          @disapprovers = FactoryBot.create_list(:mod_user, 2)
-
-          # 2 uploaders, with 2 uploads each, and 2 disapprovals on each upload.
-          @uploaders.each do |uploader|
-            FactoryBot.create_list(:post, 2, is_pending: true, uploader: uploader).each do |post|
-              FactoryBot.create(:post_disapproval, post: post, user: @disapprovers[0])
-              FactoryBot.create(:post_disapproval, post: post, user: @disapprovers[1])
-            end
-          end
-        end
-
-        should "dmail the uploaders" do
-          bot = FactoryBot.create(:user)
-          User.stubs(:system).returns(bot)
-
-          assert_difference(["@uploaders[0].dmails.count", "@uploaders[1].dmails.count"], 1) do
-            PostDisapproval.dmail_messages!
-          end
-
-          assert(@uploaders[0].dmails.exists?(from: bot, to: @uploaders[0]))
-          assert(@uploaders[1].dmails.exists?(from: bot, to: @uploaders[1]))
-        end
-      end
-
       context "#search" do
         should "work" do
           disapproval1 = FactoryBot.create(:post_disapproval, user: @alice, post: @post_1, reason: "breaks_rules")