Reintroduce clear statements that were still neccessary

spec/models/work_package/work_package_action_mailer_spec.rb

@@ -72,6 +72,8 @@ describe WorkPackage, type: :model do
 
     context 'no notification' do
       before do
+        ActionMailer::Base.deliveries.clear # clear mails sent due to prior WP creation
+
         JournalManager.send_notification = false
 
         work_package.save!

spec/requests/api/v3/work_package_resource_spec.rb

@@ -269,6 +269,7 @@ h4. things we like
         before(:each) do
           allow(User).to receive(:current).and_return current_user
           work_package
+          ActionMailer::Base.deliveries.clear # throw away mails due to work package creation
         end
 
         include_context 'patch request'