ci: Drop support for Node.js 18 (#15146)

packages/@n8n/task-runner/jest.config.js

@@ -1,6 +1,5 @@
 /** @type {import('jest').Config} */
 module.exports = {
 	...require('../../../jest.config'),
-	setupFilesAfterEnv: ['n8n-workflow/test/setup.ts'],
 	testTimeout: 10_000,
 };

packages/@n8n/task-runner/src/polyfills.ts

@@ -1,5 +0,0 @@
-// WebCrypto Polyfill for older versions of Node.js 18
-if (!globalThis.crypto?.getRandomValues) {
-	// eslint-disable-next-line @typescript-eslint/no-unsafe-assignment, @typescript-eslint/no-var-requires, @typescript-eslint/no-unsafe-member-access
-	globalThis.crypto = require('node:crypto').webcrypto;
-}

packages/@n8n/task-runner/src/start.ts

@@ -1,4 +1,3 @@
-import './polyfills';
 import { Container } from '@n8n/di';
 import { ensureError, setGlobalState } from 'n8n-workflow';