Don't use \Drupal::service('renderer')->render()

Problem/Motivation

ResponseText: The website encountered an unexpected error. Please try again later.LogicException: Render context is empty, because render() was called outside of a renderRoot() or renderPlain() call. Use renderPlain()/renderRoot() or #lazy_builder/#pre_render instead. in Drupal\Core\Render\Renderer->doRender() (line 244 of core/lib/Drupal/Core/Render/Renderer.php). Drupal\Core\Render\Renderer->render(Array, ) (Line: 377)

Steps to reproduce

Load a preview of the RSS output when building a view.

Proposed resolution

Fix the bug.

Remaining tasks

Fix the bug.

User interface changes

n/a

API changes

TBD

Data model changes

TBD