[Other] Add tests to onTest electron code

[justinkambic]

Task summary

We recently fixed a bug that caused the error messages from Playwright not to show in the recorder. This happened because we merged a change that removed an optional field from the result object.

As a follow-up to this fix we should focus on refactoring the execution.ts file to be more testable and add tests to ensure the output remains consistent when subjected to changes.

Linked resources

PR that inspired the issue: #233

Additional information

No response