MDL-78159 lib: Added missing properties for core libraries

In PHP 8.2 and later, setting a value to an undeclared class property is
deprecated and emits a deprecation notice.
So we need to add missing class properties that still need to be declared.

lib/oauthlib.php

@@ -61,6 +61,19 @@ class oauth_helper {
     protected $http;
     /** @var array options to pass to the next curl request */
     protected $http_options;
+    /** @var moodle_url oauth callback URL. */
+    protected $oauth_callback;
+     /** @var string access token. */
+    protected $access_token;
+    /** @var  string access secret token. */
+    protected $access_token_secret;
+    /** @var  string sign secret. */
+    protected $sign_secret;
+    /** @var  string nonce. */
+    protected $nonce;
+    /** @var  int timestamp. */
+    protected $timestamp;
+
 
     /**
      * Contructor for oauth_helper.