[GSK-4033] Fix correctness aggregation error

[henchaves]

Description

Related Issue

Type of Change

• 📚 Examples / docs / tutorials / dependencies update
• 🔧 Bug fix (non-breaking change which fixes an issue)
• 🥂 Improvement (non-breaking change which improves an existing feature)
• 🚀 New feature (non-breaking change which adds functionality)
• 💥 Breaking change (fix or feature that would cause existing functionality to change)
• 🔐 Security fix

Checklist

• I've read the CODE_OF_CONDUCT.md document.
• I've read the CONTRIBUTING.md guide.
• I've written tests for all new methods and classes that I created.
• I've written the docstring in Google format for all the methods and classes that I used.
• I've updated the pdm.lock running pdm update-lock (only applicable when pyproject.toml has been
  modified)

[linear]

GSK-4033 Fix correctness aggregation error

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
75.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[kevinmessiaen]

LGTM, however I'm thinking it would be better to add those check inside the parse_json_output since it has a builtin feature to ask the llm to correct the json output

[kevinmessiaen]

Switching to repr is better so we can differentiate "True" from True, also

Suggested change

	f"Error in correctness evaluation: {json_output['correctness']}. Please make sure the agent answer is correctly formatted."
	f"Error in correctness evaluation: {repr(json_output['correctness'])}. Please make sure the agent answer is correctly formatted. Correctness value should be of boolean type."