Merge branch 'zen-mode-fixture' into 'master'

Replace static fixture for zen_mode_spec

## What does this MR do?

Replace `zen_mode.html.haml` for `zen_mode_spec.js` by already existing dynamically generated fixture.

## What are the relevant issue numbers?

#24753

See merge request !7686

changelogs/unreleased/zen-mode-fixture.yml

+---
+title: Replace static fixture for zen_mode_spec
+merge_request: 7686
+author: winniehell

spec/javascripts/fixtures/zen_mode.html.haml

-.md-area
-  .zen-backdrop
-    %textarea#note_note.js-gfm-input.markdown-area
-    %a.js-zen-enter(tabindex="-1" href="#")
-      %i.fa.fa-expand
-      Edit in fullscreen
-    %a.js-zen-leave(tabindex="-1" href="#")
-      %i.fa.fa-compress

spec/javascripts/zen_mode_spec.js

@@ -6,9 +6,10 @@
   var enterZen, escapeKeydown, exitZen;
   describe('ZenMode', function() {
-    fixture.preload('zen_mode.html');
+    var fixtureName = 'issues/open-issue.html.raw';
+    fixture.preload(fixtureName);
     beforeEach(function() {
-      fixture.load('zen_mode.html');
+      fixture.load(fixtureName);
       spyOn(Dropzone, 'forElement').and.callFake(function() {
         return {
           enable: function() {
@@ -60,11 +61,11 @@
   });
   enterZen = function() {
-    return $('a.js-zen-enter').click();
+    return $('.js-zen-enter').click();
   };
   exitZen = function() { // Ohmmmmmmm
-    return $('a.js-zen-leave').click();
+    return $('.js-zen-leave').click();
   };
   escapeKeydown = function() {