refactor(config): migrate configuration files to ES module syntax

- Updated jest.config.js, postcss.config.js, and tailwind.config.js to use ES module export syntax.
- Removed unused tsconfigPaths import from vite.config.ts to streamline the configuration.

worklenz-frontend/postcss.config.js

@@ -1,4 +1,4 @@
-module.exports = {
+export default {
   plugins: {
     tailwindcss: {},
     autoprefixer: {},