Clean up of RSpec/LetSetup within spec/lib (#28447)

spec/lib/activitypub/activity/delete_spec.rb

@@ -50,6 +50,10 @@ RSpec.describe ActivityPub::Activity::Delete do
       it 'sends delete activity to followers of rebloggers' do
         expect(a_request(:post, 'http://example.com/inbox')).to have_been_made.once
       end
+
+      it 'deletes the reblog' do
+        expect { reblog.reload }.to raise_error(ActiveRecord::RecordNotFound)
+      end
     end
   end