NamingConventions/ValidVariableName: add tests using asymmetric visibility properties

This commit adds a few tests using asymmetric visibility properties (including in constructor property promotion) to the `WordPress.NamingConventions.ValidVariableName` tests. This is just to ensure that the sniff continues to apply its variable name rules when dealing with asymmetric visibility properties added in PHP 8.4.

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

Author: rodrigoprimo

WordPress/Tests/NamingConventions/ValidVariableNameUnitTest.inc

@@ -237,3 +237,11 @@ class Has_Mixed_Case_Property {
 $lähtöaika = true; // OK.
 $lÄhtÖaika = true; // Bad, but only handled by the sniff if Mbstring is available.
 $lÄhtOaika = true; // Bad, handled via transliteration of non-ASCII chars if Mbstring is not available.
+
+/*
+ * Safeguard that the sniff handles PHP 8.4+ asymmetric visibility properties correctly.
+ */
+class Acronym_AsymmetricVisibilityProperties {
+    public private(set) string $valid_name = 'bar'; // Ok.
+    public(set) string $invalidName = 'bar'; // Bad.
+}

WordPress/Tests/NamingConventions/ValidVariableNameUnitTest.php

@@ -98,6 +98,7 @@ public function getErrorList() {
 			227 => 1,
 			238 => function_exists( 'mb_strtolower' ) ? 1 : 0,
 			239 => 1,
+			246 => 1,
 		);
 	}