ISTWCMS-4208: Use StringTranslationTrait

Fixes issue introduced in 1a03da1e.

src/Form/UwContentModerationForm.php

@@ -203,12 +203,12 @@ class UwContentModerationForm extends ConfirmFormBase {
     if ($this->status) {
 
       // Return the question to see if they want to publish the node.
-      return t('Unpublish %node_title?', ['%node_title' => $node->getTitle()]);
+      return $this->t('Unpublish %node_title?', ['%node_title' => $node->getTitle()]);
     }
     else {
 
       // Return the question to see if they want to publish the node.
-      return t('Publish %node_title?', ['%node_title' => $node->getTitle()]);
+      return $this->t('Publish %node_title?', ['%node_title' => $node->getTitle()]);
     }
   }