chore: set maxWorker to 50% (#37381)

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## **Description**

Jest is resource hungry and because of that it is advised to fine tune
parallelization config in order to get the most of reliability and speed
of execution.

Not setting it up entirely can lead to random timeout issues, longer run
times, etc.
See the troubleshoot from Jest itself -
https://jestjs.io/docs/troubleshooting#tests-are-extremely-slow-on-docker-andor-continuous-integration-ci-server
Or the performance analysis on jest runners done by Adobe -
https://medium.com/adobetech/improve-jest-runner-performance-a8f56708ba94

This PR is just an initial setup, but we need to fine tune the config
for both local and CI execution.
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## **Changelog**

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## **Related issues**

Fixes:

## **Pre-merge author checklist**

- [x] I've followed [MetaMask Contributor
Docs](https://github.com/MetaMask/contributor-docs) and [MetaMask
Extension Coding
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- [x] I've completed the PR template to the best of my ability
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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
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<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> Set Jest integration tests to use maxWorkers '50%' in
`jest.integration.config.js` to limit concurrency.
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
ad45ba0. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

Author: cryptotavares

jest.integration.config.js

@@ -6,6 +6,7 @@ module.exports = {
   coverageDirectory: './coverage/integration',
   coveragePathIgnorePatterns: ['.stories.*', '.snap', '.test.(js|ts|tsx)'],
   coverageReporters: ['html', 'json'],
+  maxWorkers: '50%',
   // The path to the Prettier executable used to format snapshots
   // Jest doesn't support Prettier 3 yet, so we use Prettier 2
   prettierPath: require.resolve('prettier-2'),