Exclude polyfill for ES2022 Error cause

Although this polyfill is required for feature complete Error support, we don’t use the `.cause` property yet

```
The es-shims polyfill added the following polyfills:
  Error cause { "android":"61", "chrome":"61", "edge":"16", "firefox":"60", "ios":"10.3", "opera":"48", "safari":"10.1", "samsung":"8.2" }
```

packages/govuk-frontend/babel.config.js

@@ -45,6 +45,13 @@ module.exports = function (api) {
           // Add logging for required polyfills
           debug: isProduction,
 
+          // Browser support polyfills to exclude
+          exclude: [
+            // ES2022 Error cause is unused
+            // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error/cause
+            'Error cause'
+          ],
+
           // Replace unsupported code with polyfills
           // without modifying window globals
           method: 'usage-pure'