fix: restore missing closing brace for provisionHealthEndpoint()

The Grafana heartbeat removal deleted the method's closing brace,
causing a syntax error (unexpected token "private").

source/packages/plg_system_mokowaas/script.php

@@ -725,7 +725,7 @@ class plgSystemMokoWaaSInstallerScript implements InstallerScriptInterface
 			);
 			$db->execute();
 		}
-
+	}
 
 	private function registerActionLogExtension()
 	{