Add orderby meta_value to WP_User_Query

[wpsmith]

For some reason, we cannot easily order the WP_User_Query() by last_name without directly editing the SQL statements. However, there is an easy way to add this that would work parallel to WP_Query().

// prepare arguments
$args  = array(
	'orderby' => 'meta_value',
	'meta_key' => 'last_name',
);
$user_query = new WP_User_Query( $args );

[SergeyBiryukov]

Related: #20606, #20624

[wonderboymusic]

Makes sense, patch still applies

[hotchkissconsulting]

Tested with latest trunk, patch works

[c3mdigital]

Duplicate: #17179 See patch: ​http://core.trac.wordpress.org/attachment/ticket/17179/17179.patch

[c3mdigital]

#17179 was marked as a duplicate.

[SergeyBiryukov]

Related: #23045

[wonderboymusic]

In 25331:

Support orderby => meta_value in WP_User_Query. Adds unit test.

Props wpsmith.
Fixes #21581.

[christinecooper]

deleted