chore: don't run preview-head.html through prettier

.prettierignore

@@ -21,4 +21,4 @@
 /package.json.ember-try
 
 # prettier
-/storybook/preview-head.html
+/.storybook/preview-head.html

.storybook/preview-head.html

@@ -1,29 +1,23 @@
 <!-- This file is auto-generated by ember-cli-storybook -->
-<meta
-  name="dummy/config/environment"
-  content="%7B%22modulePrefix%22%3A%22dummy%22%2C%22environment%22%3A%22test%22%2C%22rootURL%22%3A%22%2F%22%2C%22locationType%22%3A%22none%22%2C%22EmberENV%22%3A%7B%22FEATURES%22%3A%7B%7D%2C%22EXTEND_PROTOTYPES%22%3A%7B%22Date%22%3Afalse%7D%2C%22_APPLICATION_TEMPLATE_WRAPPER%22%3Afalse%2C%22_DEFAULT_ASYNC_OBSERVERS%22%3Atrue%2C%22_JQUERY_INTEGRATION%22%3Afalse%2C%22_TEMPLATE_ONLY_GLIMMER_COMPONENTS%22%3Atrue%7D%2C%22APP%22%3A%7B%22LOG_ACTIVE_GENERATION%22%3Afalse%2C%22LOG_VIEW_LOOKUPS%22%3Afalse%2C%22rootElement%22%3A%22%23ember-testing%22%2C%22autoboot%22%3Afalse%7D%2C%22exportApplicationGlobal%22%3Atrue%7D"
-/>
+<meta name="dummy/config/environment" content="%7B%22modulePrefix%22%3A%22dummy%22%2C%22environment%22%3A%22test%22%2C%22rootURL%22%3A%22%2F%22%2C%22locationType%22%3A%22none%22%2C%22EmberENV%22%3A%7B%22FEATURES%22%3A%7B%7D%2C%22EXTEND_PROTOTYPES%22%3A%7B%22Date%22%3Afalse%7D%2C%22_APPLICATION_TEMPLATE_WRAPPER%22%3Afalse%2C%22_DEFAULT_ASYNC_OBSERVERS%22%3Atrue%2C%22_JQUERY_INTEGRATION%22%3Afalse%2C%22_TEMPLATE_ONLY_GLIMMER_COMPONENTS%22%3Atrue%7D%2C%22APP%22%3A%7B%22LOG_ACTIVE_GENERATION%22%3Afalse%2C%22LOG_VIEW_LOOKUPS%22%3Afalse%2C%22rootElement%22%3A%22%23ember-testing%22%2C%22autoboot%22%3Afalse%7D%2C%22exportApplicationGlobal%22%3Atrue%7D" />
 <link rel="stylesheet" href="./assets/vendor.css" />
 <link rel="stylesheet" href="./assets/dummy.css" />
 <script>
-  (function () {
-    var srcUrl = null;
-    var host = location.hostname || 'localhost';
-    var defaultPort = location.protocol === 'https:' ? 443 : 80;
-    var port = 4200;
-    var path = '';
-    var prefixURL = '';
-    var src = srcUrl || prefixURL + '/_lr/livereload.js?port=' + port + '&host=' + host + path;
-    var script = document.createElement('script');
-    script.type = 'text/javascript';
-    script.src = location.protocol + '//' + host + ':4200' + src;
-    document.getElementsByTagName('head')[0].appendChild(script);
-  })();
-</script>
+            (function() {
+              var srcUrl = null;
+              var host = location.hostname || 'localhost';
+              var defaultPort = location.protocol === 'https:' ? 443 : 80;
+              var port = 4200;
+              var path = '';
+              var prefixURL = '';
+              var src = srcUrl || prefixURL + '/_lr/livereload.js?port=' + port + '&host=' + host + path;
+              var script = document.createElement('script');
+              script.type = 'text/javascript';
+              script.src = location.protocol + '//' + host + ':4200' + src;
+              document.getElementsByTagName('head')[0].appendChild(script);
+            }());
+          </script>
 <script src="./testem.js"></script>
 <script src="./assets/vendor.js"></script>
-<script>
-  runningTests = true;
-  Ember.testing = true;
-</script>
-<script src="./assets/dummy.js"></script>
+<script>runningTests = true; Ember.testing=true;</script>
+<script src="./assets/dummy.js"></script>