ISTWCMS-7275: Rename "publication" to "reference" in custom block.

Updated class and form names, admin labels, and text strings to replace "publication" with "reference" for consistency and clarity in the custom block functionality. This aligns terminology with its intended purpose.

uw_custom_blocks.post_update.php

@@ -215,7 +215,7 @@ function _references_block_titles_updates_batch_temp_storage(&$context) {
  *   about nodes and revisions processed during the batch operation.
  */
 function _references_block_titles_updates_batch_end(&$context) {
-  $context['message'] = t('Successfully updated @nodes_updated/@nodes_processed. nodes', [
+  $context['message'] = t('Successfully updated @nodes_updated/@nodes_processed nodes', [
     '@nodes_updated' => $context['results']['nodes_updated'],
     '@nodes_processed' => $context['results']['nodes_processed'],
   ]);