fix(web, SafeAreaView): replace default export with named export (#3956)

## Description

`safe-area/index.ts` re-exports `SafeAreaView` as a named export:

```ts
export { SafeAreaView } from './SafeAreaView';
```

For web builds, webpack resolves `'./SafeAreaView'` to
`'./SafeAreaView.web.tsx'`, which only had a default export:

```ts
const SafeAreaView = View;
export default SafeAreaView;
```

This causes a `ModuleDependencyWarning` at build time:

```
export 'SafeAreaView' (imported as 'SafeAreaView') was not found in './safe-area/SafeAreaView' (possible exports: default)
```

This also affects `ScreenStackItem.tsx`, which does:

```ts
import { SafeAreaView } from './safe-area/SafeAreaView';
```

For web builds this resolves to the `.web` variant, again hitting the
same missing named export.

## Fix

Replace the default export with a named export in `SafeAreaView.web.tsx`
to match the native variant (`SafeAreaView.tsx`), which only has a named
export, and the package's public surface (`safe-area/index.ts`), which
only re-exports as named.

## Test plan

- [x] Verified the warning no longer appears in a web/Storybook webpack
build after this change

## Related

Found while upgrading \`react-native-screens\` to \`4.25.0-beta.1\` in
[Expensify/App#89199](Expensify/App#89199).

Co-authored-by: Cursor <[email protected]>

Author: roryabraham

src/components/safe-area/SafeAreaView.web.tsx

@@ -2,4 +2,4 @@ import { View } from 'react-native';
 
 const SafeAreaView = View;
 
-export default SafeAreaView;
+export { SafeAreaView };