Handle deprecation

Closes #3490451

src/Entity/MessageTemplate.php

@@ -288,7 +288,20 @@ class MessageTemplate extends ConfigEntityBundleBase implements MessageTemplateI
         '#format' => $item['format'] ?? 'plain_text',
         '#langcode' => $langcode,
       ];
-      $text[$key] = \Drupal::service('renderer')->renderPlain($build);
+
+      $renderInIsolation = function (array $build): MarkupInterface {
+        $renderer = \Drupal::getContainer()->get('renderer');
+        if (!method_exists('Drupal\Component\Utility\DeprecationHelper', 'backwardsCompatibleCall')) {
+          return $renderer->renderPlain($build);
+        }
+        return DeprecationHelper::backwardsCompatibleCall(
+          \Drupal::VERSION,
+          '10.3.0',
+          fn() => $renderer->renderInIsolation($build),
+          fn() => $renderer->renderPlain($build),
+        );
+      };
+      $text[$key] = $renderInIsolation($build);
     }
 
     if (isset($delta)) {