chore: updating dsrn to use named exports instead of default exports

[georgewrmarshall]

Description

This PR standardizes the export conventions across the design system by converting all default exports to named exports in the design-system-react-native package.

The primary goals of this change are:

1. Align export patterns between design-system-react and design-system-react-native
2. Make component usage more consistent and predictable for developers
3. Adopt best practices for module exports in TypeScript

Key changes include:

• Converting component exports from default to named exports
• Updating all import statements to use named imports
• Standardizing barrel exports in index.ts files
• Ensuring the root index.ts re-exports everything from components/index.ts

Allows us to do:

import {
  AvatarToken,
  AvatarTokenSize,
  BadgeNetwork,
  ButtonSize,
  ButtonIcon,
  ButtonIconSize,
  IconName,
  Text,
  TextVariant,
  TextColor,
  AvatarAccount,
  AvatarAccountVariant,
  Icon,
} from '@metamask/design-system-react-native';

Related issues

Fixes: #649

Manual testing steps

1. Build the React Native package: yarn workspace @metamask/design-system-react-native build
2. Verify that the build completes successfully
3. Run tests: yarn workspace @metamask/design-system-react-native test
4. Run storybook to check components render as necessary (storybook will error out on incorrect imports)

Screenshots/Recordings

Before

// Before - default export in component
const Component = () => { ... };
export default Component;

// Before - imports using default import
import Component from './Component';

After

// After - named export in component 
export const Component = () => { ... };

// After - imports using named import
import { Component } from './Component';

Manual storybook smoke test

My.Movie.2.mp4

Pre-merge author checklist

• I've followed MetaMask Contributor Docs
• I've completed the PR template to the best of my ability
• I've included tests if applicable
• I've documented my code using JSDoc format if applicable
• I've applied the right labels on the PR (see labeling guidelines). Not required for external contributors.

Pre-merge reviewer checklist

• I've manually tested the PR (e.g. pull and build branch, run the app, test code being changed).
• I confirm that this PR addresses all acceptance criteria described in the ticket it closes and includes the necessary testing evidence such as recordings and or screenshots.

[georgewrmarshall]

Restructuring exports to align with React package conventions. We're using named exports and intentionally omitting withThemeProvider because:

• App-level theming: Theme providers should be applied at the application root, not per-component
• Cleaner API: Provides a more consistent interface for consumers
• Performance: Prevents redundant context providers throughout the component tree
• Flexibility: Allows applications to customize theme application strategy
• Developer experience: Makes component dependencies and requirements more explicit

[georgewrmarshall]

Aligns with React package