Revert threshold values on performance suite

### What is this about?

As the performance suite on iOS was getting flaky and going over the thresholds (https://github.com/MetaMask/metamask-mobile/pull/17935), these were increased to unblock teams.
These values should be put back once the regression is solved.

### Scenario

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### Design

_No response_

### Technical Details

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### Threat Modeling Framework

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### Acceptance Criteria

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### Stakeholder review needed before the work gets merged

- [ ] Engineering (needed in most cases)
- [ ] Design
- [ ] Product
- [ ] QA (automation tests are required to pass before merging PRs but not all changes are covered by automation tests - please review if QA is needed beyond automation tests)
- [ ] Security
- [ ] Legal
- [ ] Marketing
- [ ] Management (please specify)
- [ ] Other (please specify)

### References

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Start by reviewing the performance-suite changes and regression referenced in pull request 17935, then locate the iOS threshold definitions in the repository. Confirm the regression is resolved before restoring the previous values, and run the affected iOS performance suite to verify it remains within those thresholds.

Written by the indexing model from the issue text.