I think we should not use `JPATH_COMPONENT_ADMINISTRATOR` in core model class.

The reason is, some module will use the model in component, for example, the `mod_article_latest` will use `ContentModelArticles` in helper.php.

see: https://github.com/joomla/joomla-cms/blob/master/modules/mod_articles_latest/helper.php#L30

If current page is com_weblink or others, the `JPATH_COMPONENT_ADMINISTRATOR` will return wrong path of what the module expected.