[Storybook][i18n] initialize i18n with english locale (#185033)

## Summary

We added a check to ensure that `i18n` is initialized on the browser
before any javascript code uses `i18n`. We need to do the same in the
storybook so it works properly.

To summarize in a couple of pictures 😄 

**Before PR:**

![image](https://github.com/elastic/kibana/assets/6191849/3a598dd9-963d-4f4a-aa2a-d98a3d7f379a)


**After PR:**


![image](https://github.com/elastic/kibana/assets/6191849/e0f0b4a7-69f4-4eb1-b5b6-14bdfa716caf)


cc @petrklapka

packages/kbn-storybook/src/lib/decorators.tsx

@@ -18,10 +18,11 @@ import { CoreTheme } from '@kbn/core-theme-browser';
 import { I18nStart } from '@kbn/core-i18n-browser';
 import type { AnalyticsServiceStart } from '@kbn/core-analytics-browser';
 import { KibanaRootContextProvider } from '@kbn/react-kibana-context-root';
+import { i18n } from '@kbn/i18n';
 
 const theme$ = new BehaviorSubject<CoreTheme>({ darkMode: false });
 
-const i18n: I18nStart = {
+const i18nStart: I18nStart = {
   Context: ({ children }) => <I18nProvider>{children}</I18nProvider>,
 };
 
@@ -36,14 +37,16 @@ const analytics: AnalyticsServiceStart = {
  * `globals` provided by the Storybook theme switcher to set the `colorMode`.
  */
 const KibanaContextDecorator: DecoratorFn = (storyFn, { globals }) => {
+  // TODO: Add a switcher to see components in other locales or pseudo locale
+  i18n.init({ locale: 'en', messages: {} });
   const colorMode = globals.euiTheme === 'v8.dark' ? 'dark' : 'light';
 
   useEffect(() => {
     theme$.next({ darkMode: colorMode === 'dark' });
   }, [colorMode]);
 
   return (
-    <KibanaRootContextProvider {...{ theme: { theme$ }, analytics, i18n }}>
+    <KibanaRootContextProvider {...{ theme: { theme$ }, analytics, i18n: i18nStart }}>
       {storyFn()}
     </KibanaRootContextProvider>
   );

packages/kbn-storybook/tsconfig.json

@@ -17,6 +17,7 @@
     "@kbn/repo-info",
     "@kbn/dev-cli-runner",
     "@kbn/core-theme-browser",
+    "@kbn/i18n",
     "@kbn/i18n-react",
     "@kbn/core-i18n-browser",
     "@kbn/react-kibana-context-root",