🦙 fix: Update Title Message Role for Ollama if None Provided

[danny-avila]

Summary

Closes #3510

Addresses issue with llama3.1 not generating titles due to system message role

• Modified the OpenAIClient.js file to update the role property in the instructionsPayload.
• Implemented a conditional check to set the role to 'user' if isOllama is true and titleMessageRole is not explicitly passed.
• Maintained the default 'system' role for non-Ollama models to ensure backward compatibility.
• This fix resolves the issue where llama3.1 was not generating titles due to not being able to handle system messages as the only message in the payload

Testing

To test this change:

1. Set up an Ollama endpoint in LibreChat.
2. Initiate a conversation using the llama3.1 model.
3. Verify that the conversation title is generated correctly.

Additionally, ensure that title generation still works as expected for non-Ollama models.

• My code adheres to this project's style guidelines
• I have performed a self-review of my own code
• My changes do not introduce new warnings
• I have tested my changes to ensure they resolve the issue with llama3.1 title generation
• Local unit tests pass with my changes