Update migration guide and refactor portable stories to use initialGlobals for locale configuration instead of globalTypes defaultValue.

MIGRATION.md

@@ -470,7 +470,27 @@ export const preview = {
 };
 ```
 
-Additionally loading `globals` from globalTypes isn't supported in portable stories anymore. Use `initialGlobals` instead.
+Additionally loading the defaultValue from `globalTypes` isn't supported anymore. Use `initialGlobals` instead to define the defaultValue.
+
+```diff
+// .storybook/preview.js
+export default {
++ initialGlobals: {
++   locale: 'en'
++ },
+  globalTypes: {
+    locale: {
+      description: 'Locale for components',
+-     defaultValue: 'en',
+      toolbar: {
+        title: 'Locale',
+        icon: 'circlehollow',
+        items: ['es', 'en'],
+      },
+    },
+  },
+}
+```
 
 ### Icon System Updates
 

test-storybooks/portable-stories-kitchen-sink/react/.storybook/preview.tsx

@@ -12,10 +12,12 @@ const preview: Preview = {
       </div>
     ),
   ],
+  initialGlobals: {
+    locale: 'en',
+  },
   globalTypes: {
     locale: {
       description: 'Locale for components',
-      defaultValue: 'en',
       toolbar: {
         title: 'Locale',
         icon: 'circlehollow',

test-storybooks/portable-stories-kitchen-sink/react/stories/Button.test.tsx

@@ -55,7 +55,7 @@ describe('projectAnnotations', () => {
 
   it('renders with custom projectAnnotations via composeStory params', () => {
     const WithPortugueseText = composeStory(stories.CSF2StoryWithLocale, stories.default, {
-      globalTypes: { locale: { defaultValue: 'pt' } },
+      initialGlobals: { locale: 'pt' },
     });
     const { getByText } = render(<WithPortugueseText />);
     const buttonElement = getByText('Olá!');