Fix entity load for Views entity access check

Just spotted that there is actually a bug in the way we load entities when the " Additional access checks on result entities" option is enabled for a view. This is the code in question:

      if (!empty($this->options['entity_access']) && ($entity_type = $this->index->getEntityType())) {
        $entity = entity_load($entity_type, array($id));
        if (!entity_access('view', $entity_type, $entity[$id])) {
          continue;
        }
      }

$id here is the datasource's item ID for the item – but that doesn't need to be the same as the item's entity ID. E.g., if you have a multilingual index created through the Search API ET module, the item IDs also contain the items' language codes, thus making them invalid when used as entity IDs. So, in such cases, the above code won't work and all items would be rejected, an empty result displayed.