new prefix-agnostic config entity loader

config.inc.php

<?php
/**
 * Loads the correct type of ConfigEntity from a full configuration object name.
 *
 * ConfigEntity expects that the id passed to entity_load() will not include the
 * config prefix used by the entity type being loaded. This is unhelpful for
 * calling code that has the fully prefixed configuration object name and can
 * not reliably know the specific type of ConfigEntity to load.
 *
 * This function figures out which type of entity the configuration object
 * corresponds to, then performs the entity_load().
 *
 * Note: this should only be used if the calling code CANNOT safely know what
 * type of ConfigEntity it should be loading ahead of time. Otherwise, use
 * entity_load() directly.
 *
 * @param $name
 *   The full configuration object name, including prefix.
 *
 * @return \Drupal\Core\Config\Entity\ConfigEntityInterface
 */
function config_load_entity_by_name($name) {
  $entity = array_filter(entity_get_info(), function($entity_info) use ($name) {
    return (isset($entity_info['config_prefix']) && strpos($name, $entity_info['config_prefix'] . '.') === 0);
  });

  list($type, $info) = each($entity);
  $id = substr($name, strlen($info['config_prefix'] . '.'));

  return entity_load($type, $id);
}