MC-4014: PageBuilder Performance Is Bad With Minimal Content

- Remove attribute from DOM

Author: davemacaulay

app/code/Magento/PageBuilder/view/adminhtml/web/template/page-builder.html

@@ -5,8 +5,7 @@
  */
 -->
 <div class="pagebuilder-stage-wrapper"
-     css="'stage-full-screen': isFullScreen"
-     data-domObserver="false">
+     css="'stage-full-screen': isFullScreen">
     <div class="admin__field pagebuilder-header">
         <i click="toggleFullScreen.bind($data)" css="'icon-pagebuilder-fullscreen': !isFullScreen(), 'action-close': isFullScreen()"></i>
     </div>