Extending support for Paypal Sandbox

app/config/providers.php

@@ -113,6 +113,14 @@ return [ // Ordered by ABC.
         'beta' => false,
         'mock' => false
     ],
+    'paypal_sandbox' => [
+        'developers' => 'https://developer.paypal.com/docs/api/overview/',
+        'icon' => 'icon-paypal_sandbox',
+        'enabled' => true,
+        'form' => false,
+        'beta' => false,
+        'mock' => false
+    ],
     'salesforce' => [
         'developers' => 'https://developer.salesforce.com/docs/',
         'icon' => 'icon-salesforce',

src/Appwrite/Auth/OAuth2/Paypal.php

@@ -22,7 +22,7 @@ class Paypal extends OAuth2
         'live' => 'https://api.paypal.com/v1/',
     ];
 
-    private $environment = 'live';
+    protected $environment = 'live';
 
     /**
      * @var array

src/Appwrite/Auth/OAuth2/PaypalSandbox.php

@@ -0,0 +1,19 @@
+<?php
+
+namespace Appwrite\Auth\OAuth2;
+
+use Appwrite\Auth\OAuth2\Paypal;
+
+
+class PaypalSandbox extends Paypal
+{
+    protected environment = 'sandbox';
+
+    /**
+     * @return string
+     */
+    public function getName(): string
+    {
+        return 'paypal_sandbox';
+    }
+}