Widgets: Update default `link_type` for Gallery widget from `none` to `post` for consistency with `wp.media.galleryDefaults`.

Props bor0.
See #41914.
Fixes #41985.


git-svn-id: https://develop.svn.wordpress.org/trunk@41840 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/widgets/class-wp-widget-media-gallery.php

@@ -75,8 +75,8 @@ class WP_Widget_Media_Gallery extends WP_Widget_Media {
 			),
 			'link_type' => array(
 				'type' => 'string',
-				'enum' => array( 'none', 'file', 'post' ),
-				'default' => 'none',
+				'enum' => array( 'post', 'file', 'none' ),
+				'default' => 'post',
 				'media_prop' => 'link',
 				'should_preview_update' => false,
 			),