Reference output.txt in results.yaml when custom results are missing

[bajertom]

I've used @happz solution and added a simple test scenario.

Pull Request Checklist

• implement the feature
• extend the test coverage

Fixes #4753

[gemini-code-assist]

Code Review

This pull request ensures that output.txt is included in the logs when custom results are missing or a test times out. A typo was identified in the test metadata summary where result.yaml should be corrected to results.yaml.

[psss]

/packit test