Use hide class for ci variables list

app/assets/javascripts/ci_variable_list/ajax_variable_list.js

@@ -52,8 +52,8 @@ export default class AjaxVariableList {
 
   onSaveClicked() {
     const loadingIcon = this.saveButton.querySelector('.js-secret-variables-save-loading-icon');
-    loadingIcon.classList.toggle('hidden', false);
-    this.errorBox.classList.toggle('hidden', true);
+    loadingIcon.classList.toggle('hide', false);
+    this.errorBox.classList.toggle('hide', true);
     // We use this to prevent a user from changing a key before we have a chance
     // to match it up in `updateRowsWithPersistedVariables`
     this.variableList.toggleEnableRow(false);
@@ -70,7 +70,7 @@ export default class AjaxVariableList {
         status === statusCodes.BAD_REQUEST,
     })
       .then((res) => {
-        loadingIcon.classList.toggle('hidden', true);
+        loadingIcon.classList.toggle('hide', true);
         this.variableList.toggleEnableRow(true);
 
         if (res.status === statusCodes.OK && res.data) {
@@ -79,11 +79,11 @@ export default class AjaxVariableList {
         } else if (res.status === statusCodes.BAD_REQUEST) {
           // Validation failed
           this.errorBox.innerHTML = generateErrorBoxContent(res.data);
-          this.errorBox.classList.toggle('hidden', false);
+          this.errorBox.classList.toggle('hide', false);
         }
       })
       .catch(() => {
-        loadingIcon.classList.toggle('hidden', true);
+        loadingIcon.classList.toggle('hide', true);
         this.variableList.toggleEnableRow(true);
         Flash(s__('CiVariable|Error occured while saving variables'));
       });

app/views/ci/variables/_index.html.haml

@@ -2,7 +2,7 @@
 
 .row
   .col-lg-12.js-ci-variable-list-section{ data: { save_endpoint: save_endpoint } }
-    .hidden.alert.alert-danger.js-ci-variable-error-box
+    .hide.alert.alert-danger.js-ci-variable-error-box
 
     %ul.ci-variable-list
       - @variables.each.each do |variable|