archive npm logs after failure

ci/Jenkinsfile

@@ -29,6 +29,13 @@ pipeline {
                             }
                         }
                     }
+                    post {
+                        failure {
+                            dir('ui/npm_cache/_logs') {
+                                archiveArtifacts '*'
+                            }
+                        }
+                    }
                 }
             }
         }