Site Health: fix check name used for REST API permission checks.

Updates the calls to permission validation calls for the `directory-sizes` and `page-cache` routes to actually match the route names.

Follow-up to r54043 and r49154.

Props szepeviktor.
Fixes #59236

git-svn-id: https://develop.svn.wordpress.org/trunk@56489 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/rest-api/endpoints/class-wp-rest-site-health-controller.php

@@ -153,7 +153,7 @@ public function register_routes() {
 				'methods'             => 'GET',
 				'callback'            => array( $this, 'get_directory_sizes' ),
 				'permission_callback' => function() {
-					return $this->validate_request_permission( 'debug_enabled' ) && ! is_multisite();
+					return $this->validate_request_permission( 'directory_sizes' ) && ! is_multisite();
 				},
 			)
 		);
@@ -170,7 +170,7 @@ public function register_routes() {
 					'methods'             => 'GET',
 					'callback'            => array( $this, 'test_page_cache' ),
 					'permission_callback' => function () {
-						return $this->validate_request_permission( 'view_site_health_checks' );
+						return $this->validate_request_permission( 'page_cache' );
 					},
 				),
 			)