The `get_term()` mapping may result in term objects that are `null` or `WP_Error` when plugins use `get_term` or a related filter. Since `null` and error objects are not valid results for a term query, we discard them. Props GM_Alex. See #42691. git-svn-id: https://develop.svn.wordpress.org/trunk@43049 602fd350-edb4-49c9-b593-d223f7449a82