chg: [genericForm] Fallback entity to null (to model-less form) if not provided

templates/SharingGroups/add_org.php

@@ -13,8 +13,7 @@
             'submit' => [
                 'action' => $this->request->getParam('action')
             ],
-        ],
-        'entity' => null,
+        ]
     ]);
 ?>
 </div>

templates/element/genericElements/Form/genericForm.php

@@ -15,6 +15,7 @@
     $modelForForm = empty($data['model']) ?
         h(\Cake\Utility\Inflector::singularize(\Cake\Utility\Inflector::classify($this->request->getParam('controller')))) :
         h($data['model']);
+    $entity = isset($entity) ? $entity : null;
     $fieldsString = '';
     $simpleFieldWhitelist = [
         'default', 'type', 'placeholder', 'label', 'empty', 'rows', 'div', 'required'