This commit improves the message handling in the LLM class to gracefully handle
messages without 'content' or 'tool_calls' fields. Previously, the system would
raise a ValueError when encountering such messages, causing crashes when working
with models like Google's Gemini that sometimes return messages with different
structures.
Key changes:
- Reordered message processing to check for Message objects first
- Changed validation approach to silently skip malformed messages instead of crashing
- Removed the strict ValueError when content/tool_calls are missing
This change maintains compatibility with correctly formatted messages while
improving robustness when working with various LLM providers.
