Fix max retries nesting in config example

[shi-weili]

Related Issue

N/A

Summary

Fix the model client examples so max_retries is passed as client configuration instead of as a top-level component field.

Changes

• Move max_retries: 5 under config for the OmniAgent, Fara, and Azure model client examples in config.yaml.example.

How to Verify

1. Run uv run python -c 'import yaml; data = yaml.safe_load(open("config.yaml.example")); keys = ("model_config_omni", "model_config_fara", "model_config_azure_example"); assert all(data[key]["config"]["max_retries"] == 5 and "max_retries" not in data[key] for key in keys)'.
2. Confirm git diff main...HEAD -- config.yaml.example contains only the three indentation changes.

Checklist

• Tests added or updated (if applicable)
• Documentation updated (if needed)
• Verified using the steps above

[shi-weili]

Replaced by #562 after renaming the head branch to fix/model-config-max-retries.