Fix empty session_id handling

[willemcdejongh]

Description

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• Summary of changes: Clearly describe the key changes in this PR and their purpose.
• Related issues: Mention if this PR fixes or is connected to any issues (e.g., "Fixes How to switch OpenAI models #123" or "Relates to WATCH!! Viral-Madzimai Emily Trending VIRAL Video ONLINE #456").
• Motivation and context: Explain the reason for the changes and the problem they solve.
• Environment or dependencies: Specify any changes in dependencies or environment configurations required for this update.
• Impact on AI/ML components: (If applicable) Describe changes to AI/ML models and include performance metrics (e.g., accuracy, F1-score).

Fixes # (issue)

Type of change

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• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Model update
• Infrastructure change

Checklist

• My code follows Phidata's style guidelines and best practices
• I have performed a self-review of my code
• I have added docstrings and comments for complex logic
• My changes generate no new warnings or errors
• I have added cookbook examples for my new addition (if needed)
• I have updated requirements.txt/pyproject.toml (if needed)
• I have verified my changes in a clean environment

Additional Notes

Include any deployment notes, performance implications, or other relevant information: