Code Modernization: Use str_starts_with() in `WP_REST_Server::serve…

…_request()`.

Follow-up to [55703], [56834].

See #59650.

git-svn-id: https://develop.svn.wordpress.org/trunk@57126 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/rest-api/class-wp-rest-server.php

@@ -480,7 +480,7 @@ public function serve_request( $path = null ) {
 		 * Send no-cache headers if $send_no_cache_headers is true,
 		 * OR if the HTTP_X_HTTP_METHOD_OVERRIDE is used but resulted a 4xx response code.
 		 */
-		if ( $send_no_cache_headers || ( true === $method_overridden && strpos( $code, '4' ) === 0 ) ) {
+		if ( $send_no_cache_headers || ( true === $method_overridden && str_starts_with( $code, '4' ) ) ) {
 			foreach ( wp_get_nocache_headers() as $header => $header_value ) {
 				if ( empty( $header_value ) ) {
 					$this->remove_header( $header );