General: Only use `_jsonp_wp_die_handler()` for JSONP REST API requests.

Props mdawaffe, peterwilsoncc.
Merges [51740] to the 5.8 branch.
Built from https://develop.svn.wordpress.org/branches/5.8@51741


git-svn-id: http://core.svn.wordpress.org/branches/5.8@51349 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/functions.php

@@ -3554,9 +3554,9 @@ function wp_die( $message = '', $title = '', $args = array() ) {
 		 * @param callable $function Callback function name.
 		 */
 		$function = apply_filters( 'wp_die_json_handler', '_json_wp_die_handler' );
-	} elseif ( wp_is_jsonp_request() ) {
+	} elseif ( defined( 'REST_REQUEST' ) && REST_REQUEST && wp_is_jsonp_request() ) {
 		/**
-		 * Filters the callback for killing WordPress execution for JSONP requests.
+		 * Filters the callback for killing WordPress execution for JSONP REST requests.
 		 *
 		 * @since 5.2.0
 		 *

wp-includes/version.php

@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.8.1-RC1-51723';
+$wp_version = '5.8.1-RC1-51741';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.