Remove dismissable_callout as it has become an unneeded wrapper for persistent_user_callout

app/assets/javascripts/clusters/clusters_bundle.js

 import Visibility from 'visibilityjs';
 import Vue from 'vue';
-import initDismissableCallout from '~/dismissable_callout';
+import PersistentUserCallout from '../persistent_user_callout';
 import { s__, sprintf } from '../locale';
 import Flash from '../flash';
 import Poll from '../lib/utils/poll';
@@ -62,7 +62,7 @@ export default class Clusters {
     this.showTokenButton = document.querySelector('.js-show-cluster-token');
     this.tokenField = document.querySelector('.js-cluster-token');
 
-    initDismissableCallout('.js-cluster-security-warning');
+    Clusters.initDismissableCallout();
     initSettingsPanels();
     setupToggleButtons(document.querySelector('.js-cluster-enable-toggle-area'));
     this.initApplications();
@@ -105,6 +105,12 @@ export default class Clusters {
     });
   }
 
+  static initDismissableCallout() {
+    const callout = document.querySelector('.js-cluster-security-warning');
+
+    if (callout) new PersistentUserCallout(callout); // eslint-disable-line no-new
+  }
+
   addListeners() {
     if (this.showTokenButton) this.showTokenButton.addEventListener('click', this.showToken);
     eventHub.$on('installApplication', this.installApplication);

app/assets/javascripts/clusters/clusters_index.js

 import createFlash from '~/flash';
 import { __ } from '~/locale';
 import setupToggleButtons from '~/toggle_buttons';
-import initDismissableCallout from '~/dismissable_callout';
+import PersistentUserCallout from '../persistent_user_callout';
 
 import ClustersService from './services/clusters_service';
 
 export default () => {
   const clusterList = document.querySelector('.js-clusters-list');
 
-  initDismissableCallout('.gcp-signup-offer');
+  const callout = document.querySelector('.gcp-signup-offer');
+  if (callout) new PersistentUserCallout(callout); // eslint-disable-line no-new
 
   // The empty state won't have a clusterList
   if (clusterList) {

app/assets/javascripts/dismissable_callout.js

-import PersistentUserCallout from '.persistent_user_callout';
-
-export default function initDismissableCallout(alertSelector) {
-  const alertEl = document.querySelector(alertSelector);
-  if (!alertEl) {
-    return;
-  }
-
-  new PersistentUserCallout(alertEl);
-}

app/assets/javascripts/pages/projects/index.js

-import initDismissableCallout from '~/dismissable_callout';
 import initGkeDropdowns from '~/projects/gke_cluster_dropdowns';
+import PersistentUserCallout from '../../persistent_user_callout';
 import Project from './project';
 import ShortcutsNavigation from '../../behaviors/shortcuts/shortcuts_navigation';
 
@@ -12,7 +12,9 @@ document.addEventListener('DOMContentLoaded', () => {
   ];
 
   if (newClusterViews.indexOf(page) > -1) {
-    initDismissableCallout('.gcp-signup-offer');
+    const callout = document.querySelector('.gcp-signup-offer');
+    if (callout) new PersistentUserCallout(callout); // eslint-disable-line no-new
+
     initGkeDropdowns();
   }