Issue #3042911 by maliknaik: Remove token_tree BC layer

src/Service/FillPdfAdminFormHelper.php

@@ -23,15 +23,8 @@ class FillPdfAdminFormHelper implements FillPdfAdminFormHelperInterface {
    * {@inheritdoc}
    */
   public function getAdminTokenForm() {
-    if (function_exists('template_preprocess_token_tree')) {
-      $theme_function = 'token_tree';
-    }
-    else {
-      $theme_function = 'token_tree_link';
-    }
-
     return [
-      '#theme' => $theme_function,
+      '#theme' => 'token_tree_link',
       '#token_types' => 'all',
       '#global_types' => TRUE,
     ];