…#21256)

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## **Description**
From the Home token list, if the user sets a sort/filter such as
Descending by balance, the app crashes to the generic error screen on
next render and becomes unrecoverable. Force-quitting and relaunching
does not help; only uninstall + reinstall clears the state. The crash
message indicates the Wallet view throws on `localeCompare` of `null`.

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2. What is the improvement/solution?
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## **Changelog**

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`CHANGELOG entry: Added a new tab for users to see their NFTs`
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CHANGELOG entry:

## **Related issues**

Fixes: #21218

## **Manual testing steps**

```gherkin
Feature: my feature name

  Scenario: user [verb for user action]
    Given [describe expected initial app state]

    When user [verb for user action]
    Then [describe expected outcome]
```

## **Screenshots/Recordings**

<!-- If applicable, add screenshots and/or recordings to visualize the
before and after of your change. -->

### **Before**

### **After**

## **Pre-merge author checklist**

- [ ] 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).
- [ ] 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](https://jsdoc.app/) format
if applicable
- [ ] 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]
> Update `sortAssets` to move nullish values to the end during sorting
and add tests for null handling in alphaNumeric asc/desc cases.
> 
> - **Utils**:
> - Update `app/components/UI/Tokens/util/sortAssets.ts` to treat `null`
like `undefined` (`aValue == null` / `bValue == null`) so nullish values
are always placed at the end regardless of order.
> - **Tests**:
> - Add tests in `app/components/UI/Tokens/util/sortAssets.test.ts` to
verify alphaNumeric sorting with `null` names in both ascending and
descending orders.
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
420abbc. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->