Resolved database exception related to unknown column.

Closes #3369063

src/LinkExtractorBatch.php

@@ -277,7 +277,7 @@ class LinkExtractorBatch {
     }
 
     $query->fields('base', [$entityType->getKey('id')]);
-    if (!empty($bundle)) {
+    if (!empty($bundle) && $entityType->getKey('bundle')) {
       $query->condition('base.' . $entityType->getKey('bundle'), $bundle);
     }