[feature/oauth] Implement unlinking in OAuth

PHPBB3-11673

phpBB/includes/ucp/ucp_auth_link.php

@@ -66,6 +66,9 @@ class ucp_auth_link
 				{
 					$error[] = $auth_provider->unlink_account($link_data);
 				}
+
+				// Template data may have changed, get new data
+				$provider_data = $auth_provider->get_auth_link_data();
 			}
 		}