Fix Vue vm children not found

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

js/src/router/index.ts

@@ -158,9 +158,11 @@ const router = new Router({
 
 router.beforeEach(authGuardIfNeeded);
 router.afterEach(() => {
+  if (router.app.$children[0]) {
     // eslint-disable-next-line @typescript-eslint/ban-ts-comment
     // @ts-ignore
     router.app.$children[0].error = null;
+  }
 });
 
 export default router;