Add integration part

ee/app/assets/javascripts/trials/extend_reactivate_trial/index.js

+export const shouldExtendReactivateTrialButtonMount = async () => {
+  const el = document.querySelector('.js-extend-reactivate-trial-button');
+
+  if (el) {
+    const { initExtendReactivateTrialButton } = await import(
+      /* webpackChunkName: 'init_extend_reactivate_trial_button' */ './init_extend_reactivate_trial_button'
+    );
+    initExtendReactivateTrialButton(el);
+  }
+};

ee/app/assets/javascripts/trials/extend_reactivate_trial/init_extend_reactivate_trial_button.js

+import Vue from 'vue';
+import ExtendReactivateTrialButton from 'ee/trials/extend_reactivate_trial/components/extend_reactivate_trial_button.vue';
+
+export const initExtendReactivateTrialButton = (el) => {
+  const { namespaceId, action, planName } = el.dataset;
+
+  return new Vue({
+    el,
+    render(createElement) {
+      return createElement(ExtendReactivateTrialButton, {
+        props: {
+          namespaceId: Number(namespaceId),
+          planName,
+          action,
+        },
+      });
+    },
+  });
+};