## **Description**

This PR introduces utility functions that wrap the new header components
(`HeaderCenter`, `HeaderWithTitleLeft`, `HeaderWithTitleLeftScrollable`)
to return React Navigation-compatible screen options. These utilities
will enable gradual deprecation of the `Navbar/index.js` file by
providing a cleaner, more consistent API for navigation headers.

**Motivation:**
- The current `Navbar/index.js` contains 40+ functions with inconsistent
patterns and mixed concerns
- The new header components provide a more composable and maintainable
approach
- These utility functions bridge the gap between the new components and
React Navigation's expected format

**Changes:**
- Added `getHeaderCenterNavbarOptions` - for centered titles with
optional back/close buttons
- Added `getHeaderWithTitleLeftNavbarOptions` - for left-aligned large
titles with optional back button
- Added `getHeaderWithTitleLeftScrollableNavbarOptions` - for collapsing
headers that respond to scroll
- Added unit tests for all utility functions
- Updated each component's `index.ts` to export the new utilities

## **Changelog**

CHANGELOG entry: null

## **Related issues**

Fixes: https://consensyssoftware.atlassian.net/browse/MDP-652

## **Manual testing steps**

```gherkin
Feature: Header Navigation Options Utilities

  Scenario: Developer uses getHeaderCenterNavbarOptions
    Given a React Navigation stack screen
    When developer passes getHeaderCenterNavbarOptions({ title: "Settings", onBack: () => navigation.goBack() }) to screen options
    Then the screen displays a HeaderCenter component with the title and back button

  Scenario: Developer uses getHeaderWithTitleLeftNavbarOptions
    Given a React Navigation stack screen
    When developer passes getHeaderWithTitleLeftNavbarOptions({ onBack, titleLeftProps: { title: "NFT", topLabel: "Collection" } }) to screen options
    Then the screen displays a HeaderWithTitleLeft component with large left-aligned title

  Scenario: Developer uses getHeaderWithTitleLeftScrollableNavbarOptions
    Given a React Navigation stack screen with a ScrollView
    When developer uses the hook and utility together
    Then the header collapses smoothly as the user scrolls
```

## **Screenshots/Recordings**

### **Before**

N/A - New utility functions, no visual changes

### **After**

N/A - These are developer-facing utilities that wrap existing components

## **Pre-merge author checklist**

- [x] I've followed [MetaMask Contributor
Docs](https://github.com/MetaMask/contributor-docs) and [MetaMask Mobile
Coding
Standards](https://github.com/MetaMask/metamask-mobile/blob/main/.github/guidelines/CODING_GUIDELINES.md).
- [x] I've completed the PR template to the best of my ability
- [x] I've included tests if applicable
- [x] I've documented my code using [JSDoc](https://jsdoc.app/) format
if applicable
- [x] I've applied the right labels on the PR (see [labeling
guidelines](https://github.com/MetaMask/metamask-mobile/blob/main/.github/guidelines/LABELING_GUIDELINES.md)).
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.

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> Add utilities to wrap header components into React Navigation `header`
options, with tests and updated exports.
> 
> - **Component Library**:
> - **New utilities**: Add `getHeaderCenterNavbarOptions`,
`getHeaderWithTitleLeftNavbarOptions`, and
`getHeaderWithTitleLeftScrollableNavbarOptions` that return React
Navigation-compatible `header` options.
> - **Tests**: Unit tests for each utility covering rendering,
callbacks, and prop forwarding.
>   - **Exports**: Update `index.ts` files to export the new utilities.
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
5c9b9d8. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->