test: Improve `ParseUser::become` test

[dplewis]

New Pull Request Checklist

• [ ] I am not disclosing a vulnerability.
• [ ] I am creating this PR in reference to an issue.

Issue Description

Closes: https://github.com/parse-community/parse-php-sdk/issues/478

Approach

Creates User in the cloud and become user on the client side.

TODOs before merging

• [x] Add tests

[parse-github-assistant[bot]]

Thanks for opening this pull request!

• 🎉 We are excited about your hands-on contribution!

[codecov[bot]]

Codecov Report

Patch and project coverage have no change.

Comparison is base (a269f9e) 98.48% compared to head (d0fa843) 98.48%.

:exclamation: Current head d0fa843 differs from pull request most recent head 3be590c. Consider uploading reports for the commit 3be590c to get more accurate results

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #507 +/- ## ========================================= Coverage 98.48% 98.48% Complexity 1060 1060 ========================================= Files 38 38 Lines 3225 3225 ========================================= Hits 3176 3176 Misses 49 49 ```

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[dplewis]

This is ready to merge

[parseplatformorg]

🎉 This change has been released in version 2.2.0