hide node_referenced_by_node in block placement UI

... also sort them.

islandora.module

@@ -414,16 +414,17 @@ function islandora_form_block_form_alter(&$form, FormStateInterface $form_state,
   // /admin/structure/context instead if you want to use these conditions
   // to alter block layout.
   unset($form['visibility']['content_entity_type']);
-  unset($form['visibility']['parent_node_has_term']);
-  unset($form['visibility']['node_had_namespace']);
-  unset($form['visibility']['media_has_term']);
   unset($form['visibility']['file_uses_filesystem']);
-  unset($form['visibility']['node_has_term']);
-  unset($form['visibility']['node_has_parent']);
-  unset($form['visibility']['media_uses_filesystem']);
   unset($form['visibility']['media_has_mimetype']);
-  unset($form['visibility']['node_is_islandora_object']);
+  unset($form['visibility']['media_has_term']);
   unset($form['visibility']['media_is_islandora_media']);
+  unset($form['visibility']['media_uses_filesystem']);
+  unset($form['visibility']['node_had_namespace']);
+  unset($form['visibility']['node_has_parent']);
+  unset($form['visibility']['node_has_term']);
+  unset($form['visibility']['node_is_islandora_object']);
+  unset($form['visibility']['node_referenced_by_node']);
+  unset($form['visibility']['parent_node_has_term']);
 }
 
 /**