Fix error tracking list projects service spec

This test needs a persisted project

spec/services/error_tracking/list_projects_service_spec.rb

@@ -121,7 +121,7 @@ RSpec.describe ErrorTracking::ListProjectsService do
     end
 
     context 'error_tracking_setting is nil' do
-      let(:error_tracking_setting) { build(:project_error_tracking_setting) }
+      let(:error_tracking_setting) { build(:project_error_tracking_setting, project: project) }
       let(:new_api_url) { new_api_host + 'api/0/projects/org/proj/' }
 
       before do