[Apple] Adding method to return SocialiteUser by JWT token (#962)

Provider.php

@@ -117,6 +117,23 @@ protected function getUserByToken($token)
         return json_decode(base64_decode($claims), true);
     }
 
+    /**
+     * Return the user given the identity token provided on the client
+     * side by Apple.
+     *
+     * @param string $token
+     *
+     * @throws InvalidStateException when token can't be parsed
+     *
+     * @return User $user
+     */
+    public function userByIdentityToken(string $token): SocialiteUser
+    {
+        $array = $this->getUserByToken($token);
+
+        return $this->mapUserToObject($array);
+    }
+
     /**
      * Verify Apple jwt.
      *