Fix GH-24006: Skip gh18431.phpt when libzip lacks progress callbacks (#24009)

ZipArchive::registerProgressCallback() is only available when PHP is built
against libzip 1.3.0 or newer. Skip gh18431.phpt when the method is absent
to avoid an undefined method error, as the other progress callback tests
already do.

Closes #24009

Author: lazerg

ext/zip/tests/gh18431.phpt

@@ -2,6 +2,12 @@
 GH-18431 (Registering ZIP progress callback twice doesn't work)
 --EXTENSIONS--
 zip
+--SKIPIF--
+<?php
+if (!method_exists(ZipArchive::class, 'registerProgressCallback')) {
+    die('skip progress callbacks are not supported');
+}
+?>
 --FILE--
 <?php
 $file = __DIR__ . '/gh18431.zip';