refactor: Improve typings for element-ui imports (no-changelog) (#4678)

* convert all stories to typescript

* stricter typing for element-ui imports

packages/design-system/.storybook/main.js

@@ -4,7 +4,7 @@ const path = require('path');
  * @type {import('@storybook/core-common').StorybookConfig}
  */
 module.exports = {
-	stories: ['../src/**/*.stories.mdx', '../src/**/*.stories.@(js|ts)'],
+	stories: ['../src/**/*.stories.mdx', '../src/**/*.stories.ts'],
 	addons: [
 		'@storybook/addon-links',
 		'@storybook/addon-essentials',