Pings/trackbacks: Apply KSES to all trackbacks.

Props dd32, xknown, martinkrcho, peterwilsoncc.
Merges [54525] to the 6.0 branch.

Built from https://develop.svn.wordpress.org/branches/6.0@54535


git-svn-id: http://core.svn.wordpress.org/branches/6.0@54090 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/version.php

@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.0.3-alpha-54534';
+$wp_version = '6.0.3-alpha-54535';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.

wp-trackback.php

@@ -13,6 +13,9 @@ if ( empty( $wp ) ) {
 	wp( array( 'tb' => '1' ) );
 }
 
+// Always run as an unauthenticated user.
+wp_set_current_user( 0 );
+
 /**
  * Response to a trackback.
  *