Improve performance of atomic processing service tests

spec/services/ci/pipeline_processing/shared_processing_service_tests_with_yaml.rb

 # frozen_string_literal: true
 
 RSpec.shared_context 'Pipeline Processing Service Tests With Yaml' do
+  let_it_be(:project) { create(:project, :repository) }
+  let_it_be(:user)    { project.owner }
+
   where(:test_file_path) do
     Dir.glob(Rails.root.join('spec/services/ci/pipeline_processing/test_cases/*.yml'))
   end
 
   with_them do
     let(:test_file) { YAML.load_file(test_file_path) }
-
-    let(:user)     { create(:user) }
-    let(:project)  { create(:project, :repository) }
     let(:pipeline) { Ci::CreatePipelineService.new(project, user, ref: 'master').execute(:pipeline) }
 
     before do
       stub_ci_pipeline_yaml_file(YAML.dump(test_file['config']))
-      stub_not_protect_default_branch
-      project.add_developer(user)
     end
 
     it 'follows transitions' do