MC-16152: Login Only B2B breaks Page Builder preview

- Fix static failures

Author: davemacaulay

app/code/Magento/PageBuilder/Controller/Adminhtml/Stage/Preview.php

@@ -21,6 +21,8 @@
  */
 class Preview extends \Magento\Backend\App\Action implements HttpPostActionInterface
 {
+    const ADMIN_RESOURCE = 'Magento_Backend::content';
+
     /**
      * @var \Magento\PageBuilder\Model\Stage\RendererPool
      */
@@ -66,7 +68,10 @@ class Preview extends \Magento\Backend\App\Action implements HttpPostActionInter
      * @param \Magento\PageBuilder\Model\Stage\RendererPool $rendererPool
      * @param \Magento\Store\Model\App\Emulation $emulation
      * @param \Magento\Framework\App\State $appState
-     * @param \Magento\Theme\Model\View\Design $design
+     * @param \Magento\Framework\View\DesignInterface $design
+     * @param \Magento\Framework\View\Design\Theme\ThemeProviderInterface $themeProvider
+     * @param \Magento\Store\Model\StoreManagerInterface $storeManager
+     * @param \Magento\Framework\App\Config\ScopeConfigInterface $scopeConfig
      * @param \Magento\PageBuilder\Model\Stage\PreviewRegistry $previewRegistry
      */
     public function __construct(
@@ -95,7 +100,8 @@ public function __construct(
     /**
      * Generates an HTML preview for the stage
      *
-     * @return \Magento\Framework\Controller\ResultInterface
+     * @return \Magento\Framework\App\ResponseInterface|\Magento\Framework\Controller\ResultInterface|mixed
+     * @throws \Exception
      */
     public function execute()
     {

app/code/Magento/PageBuilder/Model/Stage/PreviewRegistry.php

@@ -22,7 +22,7 @@ class PreviewRegistry
      *
      * @return string
      */
-    public function getPreviewArea()
+    public function getPreviewArea() : string
     {
         return \Magento\Framework\App\Area::AREA_FRONTEND;
     }
@@ -42,7 +42,7 @@ public function setIsPreview(bool $isPreview)
      *
      * @return bool
      */
-    public function getIsPreview()
+    public function isPreview() : bool
     {
         return $this->isPreview;
     }

app/code/Magento/PageBuilder/Plugin/DesignLoader.php

@@ -70,7 +70,7 @@ public function beforeCreate(
         string $imageId,
         array $attributes = null
     ) {
-        if ($this->previewRegistry->getIsPreview()) {
+        if ($this->previewRegistry->isPreview()) {
             $this->appState->emulateAreaCode(
                 $this->previewRegistry->getPreviewArea(),
                 [$this, 'loadDesignConfig']