fix(workflowengine): use constant to render template

Signed-off-by: Daniel Kesselberg <mail@danielkesselberg.de>

Author: kesselb

apps/workflowengine/lib/Settings/ASettings.php

@@ -77,7 +77,7 @@ public function getForm(): TemplateResponse {
 			$this->urlGenerator->linkToDocs('admin-workflowengine')
 		);
 
-		return new TemplateResponse(Application::APP_ID, 'settings', [], 'blank');
+		return new TemplateResponse(Application::APP_ID, 'settings', [], TemplateResponse::RENDER_AS_BLANK);
 	}
 
 	/**