[e2e] Different OS ends ups with slightly different funds amount representation

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### What is this about?

When running swap tests with Anvil, the final funds result differs based on the OS. So the test is stable in local but when running in another OS the results in funds changes slightly (like by 0.00001 ETH). We don't know why this is happening, hence this ticket. To investigate the reason and find a solution / answer to this behaviour.

More context, conversation in GH:
https://github.com/MetaMask/metamask-extension/pull/31278#discussion_r2013598586

### Scenario

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### Design

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### 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 reproducing the swap tests with Anvil on the affected operating systems and compare the final funds values. Read the discussion linked from PR #31278 for existing investigation context. Done means identifying the cause of the OS-dependent difference and documenting or implementing a solution that makes the result stable across operating systems.

Written by the indexing model from the issue text.