Security/NonceVerification: add test using asymmetric visibility properties

This commit adds a test using asymmetric visibility properties to the `WordPress.Security.NonceVerification` tests. This is just to ensure that the sniff continues to ignore PHP 8.4+ asymmetric visibility properties.

The sniff was already handling asymmetric visibility properties correctly, and no change to the sniff code is needed.

Author: rodrigoprimo

WordPress/Tests/Security/NonceVerificationUnitTest.8.inc

@@ -3,4 +3,5 @@
 class IgnoreProperties {
 	public $_GET = array( 'key' => 'something' ); // OK.
 	public $_POST; // OK.
+	public private(set) string $_REQUEST; // Ok.
 }