fix(web): avoid eval history crash when toolUses is null

[pandego]

Please ensure you have read the contribution guide before creating a pull request.

Link to Issue or Description of Change

1. Link to an existing issue (if applicable):

• Closes: Playground eval history: clicking failed eval result crashes with 'e is not iterable' in formatToolUses #4657
• Related: Playground eval history: clicking failed eval result crashes with 'e is not iterable' in formatToolUses #4657

2. Or, if no issue exists, describe the change:

Problem:
Failed eval history entries can crash the web UI when intermediateData.toolUses is missing/null. formatToolUses currently iterates directly over that value and throws TypeError: e is not iterable.

Solution:
Add a null guard in formatToolUses so missing toolUses is treated as an empty list.

Testing Plan

Unit Tests:

• I have added or updated unit tests for my change.
• All unit tests pass locally.

Passed locally:

• .venv/bin/pytest tests/unittests/evaluation/test_eval_config.py
• Result: 7 passed

Manual End-to-End (E2E) Tests:

Not run in this environment. This patch is a minimal defensive guard on the affected formatter path.

Checklist

• I have read the CONTRIBUTING.md document.
• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas.
• I have added tests that prove my fix is effective or that my feature works.
• New and existing unit tests pass locally with my changes.
• I have manually tested my changes end-to-end.
• Any dependent changes have been merged and published in downstream modules.

Additional context

This is intentionally minimal (1-line behavior change) to reduce risk and keep review focused.

[gemini-code-assist]

Note

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