Show defined but empty values for constants in Site Health

[Presskopp]

Right now, for example if DB_COLLATE is defined as '', the value will not be shown in the WordPress Constants list, there's just an empty space. What about exchanging empty, but defined values for "Defined, but empty" or "empty value" or something similar for more clarity?

Patching class-wp-debug-data.php, ~L. 333 does the job:

'value' => ( defined( 'DB_COLLATE' ) ? ( DB_COLLATE === '' ? __( 'Defined as empty' ) : DB_COLLATE ) : __( 'Undefined' ) ),

[Presskopp]

Of course if this would be welcomed, debug should also be altered

This patch is mainly to test providing patches using github