Reject set_flags step when restoring projects after a PR was reopend

There is no project that should be restored for the set_flags step in a workflow,
when a PR is reopened on the SCM. There for it should be one of the steps that gets
rejected when restoring. This will also fix an issue, since the target_project_name method
of the SetFlags is private and expects to get passed a keyword argument, which all
other steps don't.

Fixes #13338

src/api/app/models/workflow.rb

@@ -130,7 +130,9 @@ def restore_target_projects
     token_user_login = token.executor.login
 
     # Do not process steps for which there's nothing to do
-    processable_steps = steps.reject { |step| step.instance_of?(::Workflow::Step::ConfigureRepositories) || step.instance_of?(::Workflow::Step::RebuildPackage) }
+    processable_steps = steps.reject do |step|
+      step.instance_of?(::Workflow::Step::ConfigureRepositories) || step.instance_of?(::Workflow::Step::RebuildPackage) || step.instance_of?(::Workflow::Step::SetFlags)
+    end
     target_project_names = processable_steps.map(&:target_project_name).uniq.compact
     target_project_names.each do |target_project_name|
       Project.restore(target_project_name, user: token_user_login)