DTL page : fix dynamic background

public/site/blueprints/pages/design-to-light.yml

@@ -11,7 +11,7 @@ tabs:
             width: 2/3
             required: true
           background:
-            label: Background image
+            label: Image d'arrière-plan
             type: files
             multiple: false
             width: 1/3

public/site/templates/design-to-light.json.php

@@ -29,7 +29,8 @@ foreach ($page->presentation()->toLayouts() as $layout) {
 }
 
 $specificData = [
-  "presentation" => $presentation
+  "presentation" => $presentation,
+  "background" => $page->background()->isNotEmpty() ? getFileData($page->background()->toFile()) : null
 ];
 
 $pageData = array_merge($genericData, $specificData);