Internationalisation of integrations directory

This is one of many MRs opened in order to improve the overall
internationalisation of the GitLab codebase.

i18n documentation
https://docs.gitlab.com/ee/development/i18n/externalization.html

app/assets/javascripts/integrations/integration_settings_form.js

 import $ from 'jquery';
 import axios from '../lib/utils/axios_utils';
 import flash from '../flash';
+import { __ } from '~/locale';
 
 export default class IntegrationSettingsForm {
   constructor(formSelector) {
@@ -65,10 +66,10 @@ export default class IntegrationSettingsForm {
    * Toggle Submit button label based on Integration status and ability to test service
    */
   toggleSubmitBtnLabel(serviceActive) {
-    let btnLabel = 'Save changes';
+    let btnLabel = __('Save changes');
 
     if (serviceActive && this.canTestService) {
-      btnLabel = 'Test settings and save changes';
+      btnLabel = __('Test settings and save changes');
     }
 
     this.$submitBtnLabel.text(btnLabel);
@@ -105,7 +106,7 @@ export default class IntegrationSettingsForm {
 
           if (data.test_failed) {
             flashActions = {
-              title: 'Save anyway',
+              title: __('Save anyway'),
               clickHandler: e => {
                 e.preventDefault();
                 this.$form.submit();
@@ -121,7 +122,7 @@ export default class IntegrationSettingsForm {
         this.toggleSubmitBtnState(false);
       })
       .catch(() => {
-        flash('Something went wrong on our end.');
+        flash(__('Something went wrong on our end.'));
         this.toggleSubmitBtnState(false);
       });
   }

locale/gitlab.pot

@@ -7931,6 +7931,9 @@ msgstr ""
 msgid "Save Changes"
 msgstr ""
 
+msgid "Save anyway"
+msgstr ""
+
 msgid "Save application"
 msgstr ""
 
@@ -8962,6 +8965,9 @@ msgstr ""
 msgid "Test failed."
 msgstr ""
 
+msgid "Test settings and save changes"
+msgstr ""
+
 msgid "TestHooks|Ensure one of your projects has merge requests."
 msgstr ""