Use get_comment_type() when comparing updating comment status

[joehoyle]

Currently we don't allow updating a comment type, however in the update
code we are checking the raw value vs get_comment_type() which means a
comment of type "comment" can not be updated, as that's actually an
empty value in the database.

[rachelbaker]

Related core ticket that would be the IDEAL solution: https://core.trac.wordpress.org/ticket/38200

[rachelbaker]

@joehoyle the default value for the type parameter is '' in the schema, that should be updated to be comment to match. https://github.com/WP-API/WP-API/blob/develop/lib/endpoints/class-wp-rest-comments-controller.php#L925

[joehoyle]

@rachelbaker I also had to modify prepare_item_for_database to set type to an empty string in the event of comment. Turns out wp_insert_comment( [ type => 'comment' ] ) breaks things a lot!

[joehoyle]

@WP-API/amigos #reviewmerge