refactor(frontend): scripts -> utility

packages/frontend/src/utility/test-utils.ts

@@ -0,0 +1,9 @@
+/*
+ * SPDX-FileCopyrightText: syuilo and misskey-project
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+export async function tick(): Promise<void> {
+	// eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
+	await new Promise((globalThis.requestIdleCallback ?? setTimeout) as never);
+}