tests: fix artist ban tests.

test/unit/artist_test.rb

@@ -66,6 +66,7 @@ class ArtistTest < ActiveSupport::TestCase
         @post = FactoryBot.create(:post, :tag_string => "aaa")
         @admin = FactoryBot.create(:admin_user)
         @artist.ban!(banner: @admin)
+        perform_enqueued_jobs
         @post.reload
       end
 

test/unit/post_test.rb

@@ -547,6 +547,7 @@ class PostTest < ActiveSupport::TestCase
           CurrentUser.scoped(FactoryBot.create(:admin_user)) do
             @artist = FactoryBot.create(:artist)
             @artist.ban!
+            perform_enqueued_jobs
           end
           @post = FactoryBot.create(:post, :tag_string => @artist.name)
         end