More Webhook API Changes

- Updated API Models with Fixes
- Updated Samples
- Additional Functional Tests

sample/notifications/DeleteAllWebhooks.php

@@ -0,0 +1,24 @@
+<?php
+
+// # Delete All Webhook Sample
+// This is a sample helper method, to delete all existing webhooks, because of limited number of webhooks that are allowed per app.
+// To properly use the sample, change the clientId and Secret from bootstrap.php file with your own app ClientId and Secret.
+
+// ## Get Webhook Instance
+
+/** @var \PayPal\Api\WebhookList $webhookList */
+$webhookList = require 'ListWebhooks.php';
+
+// ### Delete Webhook
+try {
+    foreach ($webhookList->getWebhooks() as $webhook) {
+        $webhook->delete($apiContext);
+    }
+} catch (Exception $ex) {
+    ResultPrinter::printError("Deleted all Webhooks", "WebhookList", null, null, $ex);
+    exit(1);
+}
+
+ResultPrinter::printResult("Delete all Webhook, as it may have exceed the maximum count.", "WebhookList", null, null, null);
+
+return $output;