fix: datasets permission is missing (#7751)

api/services/dataset_service.py

         return datasets.items, datasets.total
 
     @staticmethod
-    def create_empty_dataset(tenant_id: str, name: str, indexing_technique: Optional[str], account: Account):
+    def create_empty_dataset(
+        tenant_id: str, name: str, indexing_technique: Optional[str], account: Account, permission: Optional[str]
+    ):
         # check if dataset name already exists
         if Dataset.query.filter_by(name=name, tenant_id=tenant_id).first():
             raise DatasetNameDuplicateError(f"Dataset with name {name} already exists.")
         dataset.tenant_id = tenant_id
         dataset.embedding_model_provider = embedding_model.provider if embedding_model else None
         dataset.embedding_model = embedding_model.model if embedding_model else None
+        dataset.permission = permission if permission else DatasetPermissionEnum.ONLY_ME
         db.session.add(dataset)
         db.session.commit()
         return dataset